I should have thought the present-day Arabic numbering would be supported if Arabic is one of the languages you have chosen. Give the following a try if you haven't done so already:
First, select an Arabic font. For this, you will need beforehand to choose Arabic (of your regional variant, say) among the 5 languages the installation software prompts you to work with. Note a sticking point with U.A.E. Arabic.
Secondly, go into the "Home" tab, find "Formatting" (2nd or third along from the left-hand side. There, in the English interface at any rate, you have "LRM" (European way round) and "RLM" (Right to left, for Semitic languages).
There is also "Font Adaptation" in the View tab: clicking on the little arrow at the bottom of that tab, to the far right of that ribbon, displays a box with an option marked "Font" at the bottom. This governs the font displayed in the editor and there are options for selecting the font size.
Also in the "View" tab is "Interface language". I'm not sure whether Arabic is supported, but give it a try.
I have also tried changing the keyboard in the Windows environment, working from the "Settings" menu via the "Start" pop-up menu, "Settings", then (I think) "Region and Language". I haven't been able to display Arabic script or numerals myself, but it may be worth trying. I should mention that I run a French version of Windows 7, so I am working "backwards" from the French as it were.
I have also looked up your topic in SDL Studio support, where the relevant information seems sparse and dispersed, but you could look around there: start at SDL.com Community home page
and work through the different search options, recording your finds by copying and pasting to Notepad, say.
I am sorry if you have tried all this: I don't wish to patronise, or carry "coals to Newcastle". And I'm sorry if the information I have given here is nebulous. I hope, though, it will give you some lines to search, and I also hope others will come up with the answer that eludes me.
My very best regards, and good hunting,
Adam Warren (IanDhu - Translator 41189 Fr > UK Eng.)