>Your suggestion works very well with positive number (90% of database) but negative numbers don't show the right result.
>eg : -77442022681 should show up as EDF81882E7. Your help will be appreciated. TIA

Help file:

Transform: Converts numeric or currency values to their hexadecimal equivalents. The numeric or currency value must be positive and less than 4,294,967,296.

Carlos Alloatti