A method for routing a service request in a telecommunication system in cases where the identifier received for the destination of the service is not (or can not be) suitable for routing the service, such as when a E.164 number is received in IP based multimedia telecommunication systems. Upon reception of a service request in a telecommunications node of the telecommunication system in charge of serving control for services, a query comprising the received identifier is made to a translation database. As a result, a plurality of identifiers related to the received identifier are received that can have different formats and imply different service types. The service is further routed from said telecommunications node according to an identifier selected among said plurality of identifiers that contains the primarily received identifier in the user name portion.