WHMCS / Wordpress Intergration

I am looking at either getting a currently running WHMCS intergrated with a New Wordpress installation. WHMCS does supply some code to intergrate but when you click on the link supplied it then goes to the WHMCS theme instead of keeping the Wordpress theme. I would like WHMCS to, if possible, use the Wordpress theme and if I change the theme in Wordpress the theme in WHMCS to change. From my limited knowledge it is the header and page buttons that need to be shared. If you want to see the pages I am after I can supply page links, and more information if required. Here is a link to the WHMCS forum with others wanting the same:- [login to view URL] I do not want to share the login details just share the theme.