Sorry for the title, I've search over the developers manual but still i haven't found anything that will help me create my own payment module. Any help will be appreciated.
Payment modules are extensions in AbanteCart
You can review document wiki with AbanteCart architecture and extension system
http://docs.abantecart.com/pages/developer/architecture.html
You can use extension developer tool as extension creation wizard
https://github.com/abantecart/developer_tools_extension