An apparatus and a method for relay service in a wireless communication system are provided. The method includes performing a first search in response to initiating a communication session between an agent and a customer. A digital processing platform de-couples these signals to permit recovery of the original payloads. The retention structure includes at least one relief formed on the cylindrical body and presenting, as seen from the end, an overall circular contour so as to have locally an increased diameter compared to the diameter of the cylindrical body. The air flow passage is axially offset from a tank inlet. The Factor IXa can be produced by proteolytically activating recombinantly-produced Factor IX.