I have not tried anything with Arabic before, but as no one else has advised you yet I will try a few general notes which hopefully will help.
On the http://www.unicode.org/versions/Unicode4.1.0/ web page is the Unicode specification in electronic form.
Arabic is in Chapter 8.
http://www.unicode.org/versions/Unicode4.0.0/ch08.pdf
On the http://www.unicode.org/charts/ web page are links for four pdf documents with the code point allocations.
http://www.unicode.org/charts/PDF/U0600.pdf
http://www.unicode.org/charts/PDF/U0750.pdf
http://www.unicode.org/charts/PDF/UFB50.pdf
http://www.unicode.org/charts/PDF/UFE70.pdf
Now, I have not read the above five documents at the time of writing.
I will try to show you how to add a place for a character from the http://www.unicode.org/charts/PDF/UFB50.pdf file into a new Font Creator 5.0 font. I shall try to use a U+FB50 character. I do not know whether you need that character in your font. I am simply showing the technique.
Start Font Creator 5.0
File | New to start a new font.
Insert | Glyphs… and click OK, giving one new glyph at the end.
Move to the last glyph of the font, that is, the new glyph, and highlight it.
Right click and choose Properties…
Select the Mappings panel.
In the box with the 0 add xFB50 after the 0 without deleting the 0.
Click the Add button
Click OK
To add a place for U+FB51 do the following.
Insert | Glyphs… and click OK, giving one new glyph at the end.
Move to the last glyph of the font, that is, the new glyph, and highlight it.
Right click and choose Properties…
Select the Mappings panel.
In the box with the 0 add xFB51 after the 0 without deleting the 0.
Click the Add button
Click OK
This is slow and laborious yet works, so will hopefully be of help to get you started.
When you have added as many as you wish, do the following.
Format | Post…
Click on Generate Names and then click on OK.
Save the font.
You may need to use Format | Settings… and then choose the Header panel and consider the part at the top right about Font direction hint. I am unsure as to what to advise yet “Only strong left to right” may well need changing. If I had to guess I would guess at “Fully mixed directional glyphs”, simply so that the font is not biased one way or the other. If there are Latin characters in the font as well that might well be the best choice.
As far as I know, the idea with Arabic is to use an advanced font format which handles ligatures. Font Creator 5.0 does not do that. Yet I know almost nothing about Arabic. I have simply tried to show you how to add in places for the glyphs in a font made using Font Creator 5.0.
I hope that this helps.
William Overington
17 March 2006