I am beginner of Windows device driver program and I don't use Ericsson's Application Toolkit.
But I used EXtended System's BlueSDK before.
In my thinking, you might use a method of hooking a port.
You use two com port for that. One is null modem, the other is bluetooth protocol stack.
You must write a windows VxD which transfer data from a null modem port to the upper layer function of bluetooth stack instead of writing a NDIS miniport driver.
If you want to know about this method in detail, you contact a windows device driver programmer.