Now with b4i v2.00 I've just seen a new text (I don't remember if it was there before) at compile time:
Note that it is not possible to install apps signed with a store certificate.
You can download the ipa file with Tools - Build Server - Download Last Build.
This message always appears when you compile in Release mode. It reminds you that you cannot install store signed apps on the device (the compiler doesn't know whether you are using a store key or not).