In previous versions of Excel (I'm now using Excel 2007 under Windows Vista),
a file called "PERSONAL.XLS" placed in the "XLSTART" folder was used to store
all those macros and user-defined functions that were employed in formulas by
different workbooks.

I tried the same with Excel 2007. The resulting file was labelled
"PERSONAL.XLSB". Unfortunately, things don't seem to be working properly.

The user-defined functions I stored in "PERSONAL.XLSB" aren't available when
I open a regular workbook (as usual, "PERSONAL.XLSB" is loaded "hidden"
state). However, when I "unhide" "PERSONAL.XLSB" all user-defined functions
are readily available. BTW, the VBA module in my "PERSONAL.XLSB" is properly
digitally signed.

Last but not least, all my workbooks are still in the XLS format (Excel is
loaded in compatibility mode).

Thanks.