micro-usb headset on android 2.3
I believe this is impossible.
The headset requires power from the device. Android versions before 3.1 state that they can not support powering the usb bus.
From the developer guide:

When the Android-powered device is in host mode, it acts as the USB host and powers the bus. When the Android-powered device is in USB accessory mode, the connected USB hardware (an Android USB accessory in this case) acts as the host and powers the bus.
USB accessory and host modes are directly supported in Android 3.1 (API level 12) or newer platforms. USB accessory mode is also backported to Android 2.3.4 (API level 10) as an add-on library to support a broader range of devices. Device manufacturers can choose whether or not to include the add-on library on the device's system image.

unless there is a custom android OS that supports usb host mode, I believe what I'm trying to achieve is impossible