How to use MacFusion with a proxy

[sfjd]

I can access the host with ssh by using the -F option. For instance,

ssh -F ~/.ssh/config id@host

Where the config file contains the following:

ProxyCommand ~/bin/connect -H www-proxy.my_company_domain.com:80 %h %p

I tried putting the same -F option in the extra option field, but I
still cannot connect. Man sftp indicates that it supports the same -F
option as ssh.

What am I doing wrong?