Function Keys binding in Xfce Terminal

[Hassen]

I need to disable the function keys binding in xfce terminal, eg. F1 is  
set for Help and I need to use that key for my application,

I tried this  
http://superuser.com/questions/562069/disable-f1-on-xfce-terminal but it  
doesn't seems to work for me,

Im using xfce4-terminal 0.6.2 under FreeBSD.

Many thanks,
Hassen