So one of the most common questions we get from OEMs about WiFi, GPRS and ActiveSync is that on a bunch of devices, connecting to desktop ActiveSync turns off WiFi and GPRS. In fact, WiFi doesn't just turn off, it disappears from settings entirely, making it seem like there's no WiFi hardware on the device at all. This is completely intentional, and in fact a security feature.
ActiveSync uses RNDIS, which is configured as an "exclusive connection" - Connection Manager will shut down all other connections that are active when you connect to the desktop. GPRS simply gets disconnected, but the WiFi adapter is completely unbound, which is equivalent to pulling out the network card. Once the device disconnects from the desktop, the wifi adapter rebinds and shows up in settings and wireless manager again. This behavior prevents devices from being multi-homed (connected to multiple networks at the same time). When you connect to ActiveSync, you can use desktop pass-through (DTPT) to access the corporate network but connection manager will not allow a connection to the Internet to stay active at the same time as DTPT.
Ritu (Shell Apps)