I have, in one site, a PIX 515 connected to a C827H (an ADSL router doing PPPoE). This router gives access to the Net. In another site I have another PIX (a 506) and another C827H router that gave access to Net. Both sites have access to net without problems. But when I what to establish a VPN tunnel (with Ipsec) between this two sites, through the Net, I cant establish the connection. The ADSL router has their public IP negotiated with the ISP. In my lab I simulate this two connections putting two PIXs (a 520 and a 506) back-to-back with a crossover cable. I used the same configuration. The thing worked. But in my two sites that is not working. Why?
I see, in that case. I suggest you change the ACL name defined in crypto map, try not to use the same ACL that you used for nat0, it causes problem sometimes.
Try that and see if it works for you.