cvsimport using proxy?

I was going to try cvsimport over the firewall --

CVSROOT=':pserver;proxy=firewall;proxyport=3128:anoncvs@anoncvs.postgresql.org:/projects/cvsroot' cvs co -c

works fine, but it does not appear to me that cvsimport knows
about the proxied connection.  Is anybody savvy and helpful
enough to look into adding this?