VPN through a pix506E to routers and switches of a Frame Realy WAN.

Hi to everyone.

I am a newbe about Cisco PIX.

My customer has a private FR network with ten routers (1721,2610 and
3725) and twelve switches (Cisco 2950) and and and internet access
through a PIX506E at the master site.

I need to monitor and manage these devices, but i could access to the
private network only through the internet via a VPN.

Could anyone explain me how to configure the PIX 506E to terminate a
Client-to-site VPN and then accessing via telnet to all the routers
and the switches of the private WAN? Where can i find any detailed
example?

Thanks in advance.

kAKOBAN