Re-using my cellphone

Hello ! another cellphone question, but i think i havent seen this one before, so.. yorosiku onegaisimasu :)

I spent 6 months in Japan last year, during which time I had an AU cellphone with a plan. Now I want to go to Japan again, this time for a period of only 6 weeks, and i was wondering if it was possible to ''rent'' a (preferably AU, if possible it would be so great if i could use my old number and mailadress) card for in my old cellphone for 6 weeks, rather than rent a whole phone..? Its just because that phone has alot of memories and id liek to use it again out of sentiment i guess ^^;
Anyway does anyone know if its possible ??
And if not, is it even advisable to rent a phone for 6 weeks, or are there better options ?

Thank you very much in advance!

I have a Vodaphone phone that supports what you are looking for and I would think that other companies do as well.

Why not pose the question to the Customer Service people over at AU:

http://www.au.kddi.com/english/index.html

In the worse case, you can pick up a short term rental or prepaid phone from them.

Tenshi