If you utilize WHMCS, you are probably aware that the built-in Interworx module is a bit lacking. Modulesgarden (we are un-associated with them) produces an exellent Interworx Extended module. Our company has used it for about 18 months.
8Dweb does not (and never has) provide hosting and email services on the same server. In addition, we have utilized Smartermail since version 2 (now at version 16).
We had Modules Garden provide a custom Interworx_Extended with Smartermail Module that allows our WHMCS portal to now be the front-end to both excellent products. 8Dweb cannot transfer, sell or profit from the module, however, anyone interested could certainly contact Modulesgarden and ask about it. If you don’t need the Smartermail functionality, the base Interworx_Extended is well worth the price.