Is it possible for the n900 to provide a low (under 50ma) current output to charge a bluetooth adapter?

I've tried it with a female/female adapter using h-e-n, and a BT adapter that charges via usb, the battery is a 180mah 3.7 lipo ina meelectronics air-fi a9. It originally had a 100ma cell, but i swapped it out with one i had from a broken s9-hd to get a few more hours of playback time out of it. It charges fine via normal usb hubs, wall warts (ac/dc adapters), and my laptop.

Basically, can the n900 via software/wiring methods, push ~50ma out to charge this adapter? I don't mind carrying around a few extra bp-5l's, but i had to solder the 180ma cell into the bt adapter.

I have done this in the past using H-E-N with vbus boost on to give me an extra hour or two of music time on my BH-214 headset before its battery upgrade, but more importantly I have used it to emergency charge my wifes mobile phone while we were on the train, 15min gave her about three hours standby and one bar.
Just remember that the microUSB port is fragile, I wouldn't make this a common option but for emergencies as leaving a USB port plugged in to your phone puts it at serious risk.