Andrea W NC 1500 questions and details

Hi I have some questions regarding the WNC 1500. I would very much appreciate to have the answers.
Is the battery in the W NC 1500 lithium-ion or NIMH? I've had a expert headset salesman tell me that it's NIMH, and I need to confirm if this is true or not?

W NC 1500. It is stated that this headset can be used while it is charging. In this case, is the battery still being drained while it is being charged at the same time? Or is the headset being powered find a USB cable and not training any power from the battery?
I'm asking because I fear using the headset while charging might harm the batteries.

Also, the pamphlet states that the headset should not be charged with anything other than the provided USB power cable. I have many USB chargers lying around, some for cell phones. Could some of these be safe to use?

I don't want to shorten the lifespan of my battery and hope to get the longest lifetime but if this headset.

Can this headset be used on Ubuntu systems? Especially Ubuntu 12.04. I know it is not officially stated that Linux is supported, but have any of you guys over at Andrea tested this on Ubuntu or heard of any customers successfully using this on Ubuntu?
In addition to the headset drivers, I am also asking  if the audio commander software is compatible with Linux Ubuntu.

Okay here's the update. According to Andrea sales rep that I emailed, the headset can be used while charging. Now they have removed the incorrect pamphlet and replaced it with an accurate one:
I am sorry for the mix up.  Yes, the WNC-1500 can be used while charging.  The pub that is on the support console is out of date and will be updated to reflect that it can be used while charging.  Please let me know if I can help you with any thing else.  Have a good day.