Dial-up Networking

I use Red-Hat 8.0, with Gnome, and I have a dial-up internet connection.
My phone-line however is zero-dial. At first I have to dial 0 to get the
dial tone, and later the number of my service provider.How do I change my
settings to accomodate this ? I tried prefixing the number with 0 and 0, and
0- but none of these options seem to work.

Thank you.