So, after much waiting, the developer informed me that this plugin WILL NOT work with ispconfig3 version 3.5 so... there it goes my 49 dollars
For all users waiting to try this plugin on ispconfig3, DON'T.
The developer informed me that it will take some time to make this plugin works with version 3.5 so i'm basically stuck.
Anyone got the ispconfig that came with hostbill to work with ispconfig 3.5 ?