Convert from 1000 em units to 2048

I have a unicode font with lots of characters. I wish to change the em units from 1000 to 2048. When I try this, the em units change, but the outlines are all reduced. Is there someway to scale all the outlines and bearings at once?

Also, the outlines are all a little small to begin with so something has to change. I can reset the em units to something less than 1000 so that the characters will display and print larger. But I would prefer if possible to stick to the recommended 2048.

Have you looked at vanisaac’s post:
http://forum.high-logic.com:9080/t/changing-size-of-all-letters-at-once/188/5
posted on Wed Apr 02, 2003 7:18 pm?
Is that a possibility?
Joe.