Serially connected firewalls and FTP

["Mix, S.R." <MIXSR @ pjm . com>]

Hi:

We are attempting to determine how to get FTP sessions established 
end-to-end  between multiple networks, each protected by a firewall:

+-----+               +------------+               +--------+
  |   |                  |       |                  |    |
+--+  |   +----------+   |       |   +----------+   |  +------------+
|PC|  +---|FireWall a|---+       +---|FireWall b|---+  | FTP server |
+--+      +----------+               +----------+      +------------+

FireWall b is a TIS Firewall Toolkit Version 2.0

FireWall a so far has been an Eagle Raptor or another TIS FWTK.

The question is:

how does a user on the "PC" (which might include a UNIX command line) 
connect through the two firewalls to the FTP server?

Thanks,
Scott R. Mix
PJM Interconnection Association