As an alternative to dude's suggestion, I'd say "covered" in the sense of "include".
Although I'm not an expert on legal matters: If I recall it correctly, there is no need for the passive voice in that type of a sentence, i.e., "In addition, the service contract covers support services[*] required by the client, in particular if concerning the client's projects." (Personally, I'd rather say "if" here than "when".)
[*] because of the two links shown above, I am not quite sure "Unterstützungsleistung" itself would suffice in a legal context, because in the English version, the text does not speak of "other support services" than the ones already mentioned. It seems as if the German description entails more than the "support service" in English (already including equipment, facilities, and so on). Although I am not aware of the rest of the text, and if Wikipedia can be trusted here ;), I'd clearly advise that you have a glossary at the end of your document - to specify terms like that.