Deployment servers inside VPN

Hi,

I have configuration in which app, db and web servers are placed
inside corporate network  and SVN repository is placed outside.
Firewall is configured to allow connections from servers to remote SVN
repository.

Developers are using VPN clients to access corporate network. Because
of security reasons clients (developers) are not allowed to connect to
Internet through VPN, which is why they can not see SVN repository
directly.

Capistrano hangs on update_code command because it tries to retrieve
real svn revision by issuing svn info svn://xxx.xxx.xxx/repo -rHEAD
locally on developers machine.

What is best way to change this behavior. I would like to force
execution of above mentioned command on remote host (which have access
to SVN repository).

I suppose I should override query_revision method??

Thx. in advance!

Viktor