Ah, well, unfortunately ye need to export the preset in the name of y'er new account, or else FH won't understand who the preset b'longs to.
Ye could always try and rename the exported preset file with the new account name and see if that works, but I highly doubt it b'cause then there would be no protection from people stealing y'er preset.
On the other hand, and this may be a long stretch, but 'ave ye checked y'er recycle bin on y'er old computer f'er the files? Chances are the preset could still be sitting in there.