i am sorry idont know that but i think there is another solution.....
there is open source teletext plugin called goldenttx it can read arabic font successfully
but the teletext subpages in this plugin doesnt work with progdvb and it work with another dvb applications
you can see this plugin and try to know how it reads arabic and use this knowledge in progdvb teletext plugin
this is the plugin
http://rapidshare.com/files/292043731/GoldenTTX.zip
i saw in this plugin readme :
[ Unicode is supported, including continues characters(Arabic for example)for both of win9x and winNT
Can use any font as long as it supports the desired language(Unicode) and or teletext fonts ]
so you can use this plugin information as i said above and use it in progdvb teletext plugin
the readme file included in the rar file