I no longer have F2008 where I can open it, but I'd take a look in Staff attributes, which is a logical location for such things.

If you only want to hide one time signature, you may have difficulty if 2008 did not include staff styles or an option in the measure attributes for it.

If I remember correctly, it is as J Adrian says:

You can hide time signatures horizontally in all the measures of a staff (globally), in the Staff Attributes.

You can hide time signatures vertically in all the staves of a measure (globally), in the Measure Attributes.

To hide time signatures “locally” in a selected region, use a custom staff style.