Variable screen -Customization for Calendary display for current month only

Hi Gurus,

Would like to know how we can customize the calendar screen for the selection of value for the calendar date. To explain in detail..

I have created a custom variable for calendar date and made this as a mandatory variable. In the F4 help for this varaible, It showing the calender dates for October 2008 ,november 2008,december 2008 and january 2009. Since we are in the month October, we want the system to display the calender date for October only.

Please let us know how can we do this

Thanks in Advance

Raj