Routing OpenVPN (client) traffic out for Web Proxy users?

[thefunkygibbon]

Hi
I've gone through the process of creating the client openvpn to my vpn provider the tunnel is up. Great.

The next step is to only send everything via the VPN if I am using the opnsense Web Proxy.   
But I can't seem to work out how to do that, or if it is indeed possible (feels like it should be something that is)
There doesn't appear to be a way of  assigning an outbound interface for the proxy. 
I thought I could create a rule with the source being the firewalls IP.  But that didn't work as there is already an implied rule which supersedes it which allows traffic outbound from the FW normally through the default gateway.  :-(

Any pointers for the best ways to do this would be appriciated.
Thank you

[thefunkygibbon]

I can't be the only person who wanted to do this? am i??

[thefunkygibbon]

Anyone got any kind of idea on this?