All is running very fine and smoothing!
I have used the lastest Raspberry Pi Debian distro available on Download page of the official site, updated to wheezy and installed Citrix Receiver (following this post).
I have installed and used IceWeasel as browser just make an:
sudo apt-get update
sudo apt-get install iceweasel
To avoid the Citrix Receiver "SSL Error" server security certificate just shot this comman line:
sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts
After that you can use RaspberryPi with Citrix receiver! Let's login on Citrix XenApp...
Now we have to tell to IceWeasel to use by default wfica.sh (/opt/Citrix/ICAClient/wfica.sh) to open .ica files
Ok we are in!
Thanks again to David Thomas to give me access to his Citrix XenApp server!!!