domain account replication accross wan

Hi,
We just brought in a new site to our company accross a leased T1 PPP line. The line is all set up, and communication accross it works (ping, telnet, file & print) but I cannot get the BDC out there to sync with my PDC here. In server manager all I get is network path error. I called the tech support for our routers and they told me I need to set up a push pull for the site. Of course they did not say what a push pull is. Do they want me to set up a WINS push pull? would this solve my problem? Help!