www.myhost.com:2222 cannot be accessed from my work cos of firwalls. In fact, it only allows web port:80, ftp:21 .
It does not allow ssh port 22.
In Webmin, you can set it up under apache inside a folder.
So, no one needs to access webmin on www.myhost.com:10000
You can access it like www.myhost.com/webmin and then firewall has no problem.