The 30-day trial version is the fully functional Professional Edition, which includes a facility to insert characters. Using this you can easily add the Hebrew character sets (which are not included in the default font template). Anyway it is easy enough to copy and paste the required mappings from another font.
If you look in the Gallery forum, you will find some Hebrew fonts that will give you a hint on how to get started and show what can be done with FontCreator.
See also my tutorial on Scanning an Entire Alphabet. I find that copying and pasting bitmaps from IrfanView is an efficient way to get a whole alphabet from a scanned original into FontCreator.