Passive FTP - PassivePortRange - Windows Firewall

I set my passive port range to 10 ports and then opened them on the windows
firewall.
I have also opened ports 20 and 21.

With the firewall on, a passive FTP connection bombs right at the point that
the client asks for PASV.

Active connections go fine on port 20.

With the firewall off, I can see all passive traffic moving on port 21 and
the passive range that I have set.

Anybody have some insight for me?