Scroll Bar - negative to positive range?

I am trying to insert a form scroll bar with a minimum value of -1 and a positive of 1 with .1 increments, but it doesn't seem to let me put a negative number as a minimum value??

I have a printed copy of a spreadsheet showing a negative number in the reference cell, so I know it must be possible?

Can you help? This is how I have set up the properties. If i can't use the form control, I have no idea how to edit the properties of an active X control to do this. I have copied my print screen to see how I am trying to set up the settings.

Thanks. Terri