Code to show date as hh:mm when saving via macro

Hi all - I have this bit of code in a macro that is part of an 'email then save as' function in my spreadsheet. I want it to show the time with a colon in between the hours, minutes and seconds ie: 08:32:26, but as it is, an error occurs because you are not allwed to use the colon in the macro - any ideas? thanks

TempFileName = Format(Now, "dddd mmmm dd, yyyy @ hh:mm") & " " & Sourcewb.Name & " " _