Billing software ?

[mdscorp]

I used hosting controller for my reseller product because it comes with integrated billing, something my reseller customers like because it allows them to manage their custoemrs.
I like PLESK a lot and I am using it for my regular shared hosting clients, I would like to use it for my resellers but it doesn't come with billing, anybody knows an easy billing software to work with plesk or that I could offer along with pleask ?

thanks

 

[JonRohan]

modernbill is compatable with plesk.