I agree, this sounds like an encoding issue related to double byte character sets - I've never had a problem using that object in English. Seeing as Blue Prism are distributing this on the Portal you should probably raise the issue with the product support team.
In the meantime, there is nothing stopping you figuring out an implementing how to use Russian encoding. A quick google (so i could be wrong) suggests you may need to use the XMLDeclaration class to set the encoding - otherwise it will use the default. Have a play feed back to us if you figure it out.