Thought I'd confirm the same in case someone's come up with a solution thus far. No feedback yet from MTN's Tech Support either...
Wondering whether the same issue exists with the unbranded Huawei (B683), if not it might be worthwhile attempting to flash the B660 (MTN Branded) with the B683 firmware... I have been unable to find firmware online for either of these two devices though

huaweidevice.com only has a few startup manuals listed for download
I'm not experienced in Linux (which I understand is what these things run) - anyone know how to telnet into the device and change the antenna settings via telnet?