Need to create a module for GMO (japanese payment gateway)

Hi,

I need to develop a module for my payment gateway (GMO).
Can anybody tell me where to start?
I got the documentation in english and the API elements from them.
I really don't know where to start...

An other question, any idea when (about) the final 1.0 version gonna be release?

Thanks!

You can take a look at some of the other payment modules like the sedex and authorize.net SIM modules in the contribution area. Reverse engineer them, they will give you the base structure