RodC14 on "Arabic numbers in editor not working"

Hello All,
I am creating an English and Arabic site. I have managed to install multi-language support in the CMS and Arabic is working except for one problem, which is

The Roman numerals are not converted to Arabic numbers in the editor.

I refer to this post:
http://wordpress.org/support/topic/how-to-both-english-and-arabic

and tried setting DB_Charset to 'ISO 8859-6' and null but both solutions did not work.

Appreciate any help with this.

Regards,
Rod