Hi, your VPN clients connecting into the PIX will not be able to access the resources at site B because the PIX will not allow the same packets to traverse the outside interface twice. This is a feature of the PIX, if your VPN server was some other device such as a router this would work.
From reading other posts on Netpro I believe this feature will alter in version 7 of the PIX code, this is second information.
Andy