POS IP printer with iPad

We are working on printing invoice receipt - which contains both English and Arabic character, English characters printing correct but arabic characters not appear properly.

We have tried almost all character encoding set which are supported to arabic

Example:
UTF-8 [World wide standards formate for all characters]
Windows-1256
GB_18030_2000
macArabic
dosArabic
isoLatinArabic
windowsArabic
maxExtArabic
iso-8859-6
etc.

but printer not printing the arabic characters