diff --git a/src/Internal.h b/src/Internal.h
index 19f9e10..0520691 100644
--- a/src/Internal.h
+++ b/src/Internal.h
@@ -64,7 +64,7 @@ typedef struct _VIGEM_TARGET_T
     USHORT VendorId;
     USHORT ProductId;
     VIGEM_TARGET_TYPE Type;
-    DWORD_PTR Notification;
+    FARPROC Notification;
 
     std::shared_ptr<NotificationRequestPool> pool;
 
diff --git a/src/NotificationRequestPool.cpp b/src/NotificationRequestPool.cpp
index f429938..89c9b08 100644
--- a/src/NotificationRequestPool.cpp
+++ b/src/NotificationRequestPool.cpp
@@ -47,8 +47,8 @@ NotificationRequestPool::NotificationRequestPool(
         wait_handle = CreateEvent(nullptr, FALSE, FALSE, nullptr);
         // create async pending I/O request wrapper
         requests_.push_back(std::make_unique<XusbNotificationRequest>(
-            client_->hBusDevice,
-            target_->SerialNo,
+            client_,
+            target_,
             wait_handle
             ));
     }
@@ -113,22 +113,8 @@ void NotificationRequestPool::operator()()
         // grab associated request
         const auto req = requests_[index].get();
 
-        // prepare queueing library caller notification callback
-        const boost::function<void(
-            PVIGEM_CLIENT,
-            PVIGEM_TARGET,
-            UCHAR,
-            UCHAR,
-            UCHAR)> pfn = PFN_VIGEM_X360_NOTIFICATION(callback_);
-
         // submit callback for async yet ordered invocation
-        strand.post(boost::bind(pfn,
-                                client_,
-                                target_,
-                                req->get_large_motor(),
-                                req->get_small_motor(),
-                                req->get_led_number()
-        ));
+        req->post(std::move(strand));
 
         // submit another pending I/O
         req->request_async();
diff --git a/src/ViGEmClient.cpp b/src/ViGEmClient.cpp
index e4f2c98..d42ef63 100644
--- a/src/ViGEmClient.cpp
+++ b/src/ViGEmClient.cpp
@@ -481,12 +481,10 @@ VIGEM_ERROR vigem_target_x360_register_notification(
     if (target->SerialNo == 0 || notification == nullptr)
         return VIGEM_ERROR_INVALID_TARGET;
 
-    if (target->Notification == reinterpret_cast<DWORD_PTR>(notification))
+    if (target->Notification == reinterpret_cast<FARPROC>(notification))
         return VIGEM_ERROR_CALLBACK_ALREADY_REGISTERED;
 
-    // TODO: tidy up this mess
-
-    target->Notification = reinterpret_cast<DWORD_PTR>(notification);
+    target->Notification = reinterpret_cast<FARPROC>(notification);
 
     target->pool = std::make_shared<NotificationRequestPool>(
         vigem,
@@ -515,10 +513,10 @@ VIGEM_ERROR vigem_target_ds4_register_notification(
     if (target->SerialNo == 0 || notification == nullptr)
         return VIGEM_ERROR_INVALID_TARGET;
 
-    if (target->Notification == reinterpret_cast<DWORD_PTR>(notification))
+    if (target->Notification == reinterpret_cast<FARPROC>(notification))
         return VIGEM_ERROR_CALLBACK_ALREADY_REGISTERED;
 
-    target->Notification = reinterpret_cast<DWORD_PTR>(notification);
+    target->Notification = reinterpret_cast<FARPROC>(notification);
 
     std::vector<std::thread> threadList;
 
diff --git a/src/XusbNotificationRequest.cpp b/src/XusbNotificationRequest.cpp
index 9929c12..a0b75b1 100644
--- a/src/XusbNotificationRequest.cpp
+++ b/src/XusbNotificationRequest.cpp
@@ -25,26 +25,31 @@ SOFTWARE.
 
 #include "XusbNotificationRequest.h"
 #include <winioctl.h>
+#include <ViGEm/Client.h>
+#include "Internal.h"
+#include <boost/bind/bind.hpp>
+#include <boost/function.hpp>
 
 
 XusbNotificationRequest::XusbNotificationRequest(
-    HANDLE bus,
-    ULONG serial,
+    PVIGEM_CLIENT client,
+    PVIGEM_TARGET target,
     HANDLE notification
-) : parent_bus_(bus),
+) : client_(client),
+    target_(target),
     payload_(),
     overlapped_()
 {
     memset(&overlapped_, 0, sizeof(OVERLAPPED));
     overlapped_.hEvent = notification;
-    XUSB_REQUEST_NOTIFICATION_INIT(&payload_, serial);
+    XUSB_REQUEST_NOTIFICATION_INIT(&payload_, target_->SerialNo);
 }
 
 bool XusbNotificationRequest::request_async()
 {
     // queue request in driver
     const auto ret = DeviceIoControl(
-        parent_bus_,
+        client_->hBusDevice,
         IOCTL_XUSB_REQUEST_NOTIFICATION,
         &payload_,
         payload_.Size,
@@ -59,6 +64,26 @@ bool XusbNotificationRequest::request_async()
     return (!ret && error == ERROR_IO_PENDING);
 }
 
+void XusbNotificationRequest::post(boost::asio::io_service::strand strand) const
+{
+    // prepare queueing library caller notification callback
+    const boost::function<void(
+        PVIGEM_CLIENT,
+        PVIGEM_TARGET,
+        UCHAR,
+        UCHAR,
+        UCHAR)> pfn = PFN_VIGEM_X360_NOTIFICATION(target_->Notification);
+
+    // submit callback for async yet ordered invocation
+    strand.post(boost::bind(pfn,
+        client_,
+        target_,
+        payload_.LargeMotor,
+        payload_.SmallMotor,
+        payload_.LedNumber
+    ));
+}
+
 UCHAR XusbNotificationRequest::get_led_number() const
 {
     return payload_.LedNumber;
diff --git a/src/XusbNotificationRequest.h b/src/XusbNotificationRequest.h
index 479d20e..84ec8c2 100644
--- a/src/XusbNotificationRequest.h
+++ b/src/XusbNotificationRequest.h
@@ -27,16 +27,20 @@ SOFTWARE.
 
 #include <Windows.h>
 #include "ViGEm/km/BusShared.h"
+#include <boost/asio.hpp>
+#include "ViGEm/Client.h"
 
 class XusbNotificationRequest
 {
-    HANDLE parent_bus_;
+    PVIGEM_CLIENT client_;
+    PVIGEM_TARGET target_;
     XUSB_REQUEST_NOTIFICATION payload_;
     OVERLAPPED overlapped_;
 
 public:
-    XusbNotificationRequest(HANDLE bus, ULONG serial, HANDLE notification);
+    XusbNotificationRequest(PVIGEM_CLIENT client, PVIGEM_TARGET target, HANDLE notification);
     bool request_async();
+    void post(boost::asio::io_service::strand strand) const;
 
     UCHAR get_led_number() const;
     UCHAR get_large_motor() const;