authorize.net donations integration??

Has anyone done this?? -- and willing to share anything??

I need to implement this for two sites, obviously the code would be the same.

Alternatively is it feasible to find and use the VisionCart authorize.net code?? (I should ask first)

I found a forum thread about ’Shopkeeper’ and authorize.net -- is this how I would go about it etc.??

Obviously one must hide certain codes etc.

Thank you, Tom