Second IP from VPN

I'm connected via LAN to the Internet. Sometimes I additionally use a VPN connection, so my network card gets assigned a second IP. Since some of the FTP servers I use have IP restrictions, I want SmartFTP always to bind to the LAN IP instead of the VPN IP. How can this be archived? The only way it works so far is to start SmartFTP before establishing the VPN connection.

How about a proxy binded to the desired ip?

maybe that would work, but it is a little complicated. a simple "Always bind to this IP" option, as in other applications, would be nicer ...

"other applications"=?

i was not necessarily referring to other ftp clients, as for this feature the protocol should not matter. take a look at the bittorrent client abc for an example (Action -> ABC Preferences -> Advanced settings -> IP to bind to).