There is no such thing as an ICAO RTO; ICAO ceased to recognise RTO permits over 15 years ago. Individual States still issue such permits/licences to comply with ITU requirements and to ensure that operators are familiar with their own National procedures. For that reason, you will find little changeability between licences as the content and requirements differ considerably. I do recall that the German Ministry of Telecommunications did have a very nice document in English listing their requirements. I recall it was much clearer than the UK Wirelerss Telegraphy Act.
I suggest you contact the LBA. Presumably you are not a pilot or you would already have the privileges.