I have a workbook created in Excel 2003, with a number of hidden
sheets. I need this workbook to also be useable in Excel 2007.

Neither the workbook nor the hidden sheets are protected but I can
find no way to make the hidden sheets visible in 2007.

Before someone replies with Home - Format - Hide & Unhide - Unhide
Sheet... I should point out that this menu option is greyed out.

If I try to set the Visible property in the VBE to -1 - xlSheetVisible
I get the error msg: "Unable to set the Visible property of the
Worksheet class". Naturally I get the same msg if I try changing the
setting via VBA.

Is this a known problem and is there a work-around?