Source IP addresses for IKE for exchanges leaving out of the same physical interface, ie:
crypto map to-peer_a 10 ipsec-isakmp
set peer 10.1.3.1
set local-address loopback1 <-- new command
match address 100
crypto map to-peer_a 20 ipsec-isakmp
set peer 10.1.3.2
set local-address loopback2 <-- new command
match address 101
Current code allows to specify a local-address for each crypto map only, and not on a per crypto map instance, as suggested above.