Custom module

[peppos]

I need a payment module just to send the user to my payment gateway's url. I need the following values to be included in the url:

-Total amount

-Order id

 

I'm currently modifying the existing paypal url but i'm having some problems to find those values.

 

Is there a custom module that is designed to do this kind of procedure?

How can i get thos values if i want to modify the paypal script? please let me know asap

thanks