Ok I think I have done it.
It wasnt easy. Vertually no documentation and no help from WPMU (unless I pay them).
Initial tests shows it working but I am not a big user of this plugin so I worry I might be overlooking something.
If you want to test it out, I have put it on pastebin.
Installation
Unfortunately, it is not possible to hook in with a custom payment gateway outside of this plugin so until the 1.3 release (where I hope to include this) you will need to open up your gateway folder, which is located in: plugins/membership/membershipincludes/gateways/
, and create a new file called “gateway.mycredpayment.php”.
Then copy the code from pastebin and paste it in this new file and save.
You should then see a new gateway in your Membership menu that you can activate and adjust settings according to your needs.
It’s pretty simple, if the user does not have enough points to pay using points, the option to pay with points will not be visible.
At this stage, I would not recommend using this on a live site just to be safe.