Persian digits in DocBook XSL numbering!

Is it possible to change the DocBook XSL numbering language / character 
format, to have chapters or section numbers in Persian language.

I should get Unicode Persian digits in my Persian documentation, in native 
digits.

http://www.unicode.org/charts/PDF/U0600.pdf

Char   Dec.	Hex	Name
0	1632	0660	ARABIC-INDIC DIGIT ZERO
1	1633	0661	ARABIC-INDIC DIGIT ONE
2	1634	0662	ARABIC-INDIC DIGIT TWO
3	1635	0663	ARABIC-INDIC DIGIT THREE
4	1636	0664	ARABIC-INDIC DIGIT FOUR
5	1637	0665	ARABIC-INDIC DIGIT FIVE
6	1638	0666	ARABIC-INDIC DIGIT SIX
7	1639	0667	ARABIC-INDIC DIGIT SEVEN
8	1640	0668	ARABIC-INDIC DIGIT EIGHT
9	1641	0669	ARABIC-INDIC DIGIT NINE

Should I use the xsl:number lang or format in my customizing layer?
My processing system is Saxon 6.5.3, Linux, DocBook XSL 1.69.1.

Thanks

Kia Teymourian