Documents, generated by PBA during daily billing (billing and renewal orders) are not localized into account's language, and are generated in the default language <see http://kb.sp.parallels.com/115851>
Starting from PBA 5.5 update 6 it is possible to make PBA generate billing and renewal orders using account's language.
In order to enable this feature, one should connect to PBA database and execute the following statement:
update "Features" set "IsActive"=1 where "FeatureName"= 'FEA_UseAccountLanguageForBilling';
And restart PBA services:
# service pba restart
# net stop ssm /Y # net start ssm # net start pba