WebCal : not showing right day

Ciao Guys

XServe with 10.7.5 + OSX Server running

I connect the calendar with WebCal; it shows the day correct BUT the "name" of the day it's not.

For example, today it shows 19 september and it's correct BUT it calls this days "saturday".

Time zone is correct ( ROME) but the problem remain.

Pls note with iCal app it's ok; so seems to belongs only to the web interface

Any suggestion?

Rob