problem of synchronize with VSS

[C Chang]

One of my developer does not have direct link to domain which the
development is set up. He is using the VPN to connect to our web
application from outside. He edits the source file by checking out from
there and put it back in Web application. Such set up raised a major
problem for us. Because every time we need to promote his working file
to another server, I can not synchronize for our web project from
InterDev and obtain the latest version of the file nor using the "get
the latest version" menu from the InterDev. I still get the older
version with both steps. Does anyone know why? The only way I can do
are
1. Set up the map drive link from SourceSafe of Developing one to the
Web Application folder of Developing two.
2. In VSS of Dev-1 and use the "Get" button to get the latest file "To"
the Web Application (working folder) of Dev2.

It is really mind bothering. Besides, I found out this morning that
when I synchronized my Dev-1, that has set up the VSS connection, I will
actually wipe out his developing version on the Web Application (
working) folder. Does anyone have a better solution for this?

C Chang