No internet access from remotesite of vpn tunnel

[tuxmaster]

Hi folks,
my test setting is as follows:

Internet__R0__SiteA R1 VPN-Tunnel__R2___SiteB__

like "pfsense - the definitive guide" Page 242.
R= pfsense router

I need internet access from siteB, but how can i realize it?
The default gw from R1 points to R2 and vice versa
All Servers/Stations on SiteA have a default gw that points to R0 => internet access no problem
R0 has a route to siteB and the gw points to R1 => access from siteB to siteA no problem

My first approch is to install a dns/proxy server on SiteA, that works well
But how can i realize a routing solution with pfsense?

Please, can anyone give me a hint, an example??
regards, tuxmaster.