Following those specs, i found this: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140490732116#ht_5667wt_1139
I'm gonna asume its gonna work too. and its 600mAh.
Glad you found one! Tell us if you've noticed improvements in battery life, if you don't mind.
Be careful handling Lithium batteries, especially with Lithium Ion.