Comment 3 for bug 441334

"libnm-glib0" has been removed from the repositories on 2009-10-05.

I had a closer look at the source package. The "network-manager-strongswan" source package fails to build on all architectures because the build dependency "libnm-glib-vpn-dev" is missing. This dependency is incorrect because the network manager package naming in Ubuntu differs from the package naming in Debian: In Ubuntu, the "network-manager-strongswan" package should build-depend on "libnm-glib-dev" instead of "libnm-glib-vpn-dev".

I tried this:
1.) Patch "Build-Depends" of network-manager-strongswan-1.1.1-1 source package (see attachment)
2.) Build and intall network-manager-strongswan binary package
3.) Rebuild and install strongswan-nm (without changes) to get DBUS bindings right

Now network-manager-strongswan does not need libnm-glib0 anymore and works for me.