NAT on enc0 and VPN

[Andreas Schuldei <andreas_(_at_)_schuldei_(_dot_)_org>]

I am setting up a VPN. Two sites use the same private IP-range for their
networks. Both use the 192.168.1.0/24 net.

Now I figured that it should be possible to do a 
bimap enc0 192.168.1.1/32 -> 192.168.100.1/32 
(and so on for all 254 IPs)

I think that the incoming packages from 192.168.1.0/24 will be rewritten to
come from 192.168.100.0/24 and the outgoing from my network to the outside VPN
world will also apear to come from 192.168.100.0/24 as they are rewritten as
they pass over the interface.

Will this work? can I nat on enc0? Is this a good place to nat? will the
bidirectional mapping work for the VPN? Am I overlooking something?