In order to have a dyamic switchover, what you need to do is to run a dynamic routing protocol between your vpn gateway peers, along with modifying the crypto map to use a loopback interface (that loopback will be one of the networks/hosts advertised via the routing protocol). Assuming that you have both provider links up at the same time, you do this:
1. Create two loopback addresses, along with the two crypoto maps. Map1 and 2 will acutally be the same execpt Map 1 will use Looback1 and be used be applied on provider #1 inteface, while map2 will use Loopback2 and be applied on provider #2 interface. Run a routing protocol that hands out two different metrics for the loopback addresses, to allow the prioritization.
2. On the remote end, create one crypto map and allow it to have 2 peers, one for each head-end connection. It will have to also run a dynamic routing protocol to accept the advertisement from the head end.
Let me know if this helps. One thing I assume is that the remote end also has two provider interfaces, let me know if this is not the case.
