Imitating modems over network connection to intern

I have an account with an isp that allows me ftp access to webspace if I dial up to it. However, I cannot access this ftp space when using a proxy network connection to the internet i.e. when I don't have to dial up.

This is obviously a restriction to the service I have subscribed to . I would like to be able to connect to this ftp area.

Does anybody know if it is possible to emulate a modem connection over this kind of network connection to perhaps fool the ftp server? If so how can I do this?

Mark