BackgroundTransferRequest status WaitingForWiFi when TransferPreferences is set to AllowCellularAndBattery

Question

When I create a BackgroundTransferRequest, with TransferPeferences set to AllowCellularAndBattery, I sometimes still get a TransferStatus set to WaitingForWiFi. Is there any way to force the transfer to occur over 3G? This is very weird, as sometimes I start 4 transfers, and 2 of them will be fine, and the other 2 will get into the WaitingForWifi state.

Answer 1

I think the problem may be with file size - see Background Transfer Policies - there are limitations for transfer by 3G. When the file is too large TransferPreferences automaticallly changes.
http://msdn.microsoft.com/en-us/library/windowsphone/develop/hh202955(v=vs.105).aspx

For now it seems to be no way to force transmission over 3G if policies are not ok.