Change URl in WHMCS email notification

WHMCS notification emails use the original URL, and not the Wordpress integrated URL.

Very confusing for clients that sign up through one interface and URL, but then see a completely different URL and interface when they click email reminders to pay bill or change their password.

How can we change the setting in WHCMS so it sends them to the Wordpress skinned version?

I've seen another solution that offers both a WP plugin and WHMCS plugin to handle the WHMCS side of integration. Maybe this would be the only way to truly integrate WHMCS with Wordpress?