FTp with/without credentials

Hi,

I have a problem with a ftp site. We are connecting from behind a TMG server. Here are the two scenarios so far that have done:

1: We connect to the ftp site using "ftp://username:password@hostname.co.za", the site works 100%. Traffic on the TMG is allowed with no errors.

but

2: When we connect to the same address without credentials in the URL we dont get any authentication popups from the ftp server. Also on the TMG the traffic is denied by the rule created for this ftp traffic.

Please can someone assist?

Regards,
Nicus