VBA script to replace Hyperion retrieve formula's to fixed value

Hello,
I''ve got a report with Hyperion retrieve formula's and would like to have a VBA script to replace Hyperion retrieve formula's to fixed value in total workbook, but leave other (non-Hyperion retrieve formules) unharmed.

The Hyperion retrieve formula's always starts with "=HPVAL(".

What I do now is still manual work to succeed:
I first use the search function with "find all" with "HPVAL"
then CTRL+A (select all)
then I run a VBA script, like:

-----------------------
Dim ar As Range

For Each ar In Selection.Areas
ar.Value = ar.Value
Next ar
End Sub
-----------------

and do this for all sheets separately.

Can anyone help me with a VBA script to change my retrieve formula's into fixed value?
Many thanks in advance.

Regards,
Rogier