documentary evidence that his consent to a secondment had bee n obtained or sought with regard to his initial appointment. XXI.From the foregoing analysis, the Tribunal finds that, at th e time of his initial appointmen t, the Applicant was not on secondment, due to the non-existence of an agreement between the three partie s concerned, which is an essential requirement for a secondment. XXII.The question still remains whether the Applicant, in this ca se, was entitled to a probationary appointment, and whether the Respondent had a corresponding obligation to grant him such an appointmen t according to the pertinent regulations and rules. According to staff regulation 4.5(b): "The Secretary-General shall prescribe which staff member s are eligible for permanent appointments. The probationar y period for granting or confirming a permanent appointment sh all normally not exceed two years, provided that in individua l cases the Secretary-General ma y extend the probationary period for not more than one additional year." Regulation 4.5(a) provides that: "... Other staff members [than Under-Secretaries-General and Assistant Secretaries-General] shall be granted eithe r permanent or temporary appointments under such terms an d conditions consistent with these regulations as th e Secretary-General may prescribe." Staff rule 104.12(a) provides that probationary appointments: "... may be granted to persons under the age of 50 years who are recruited for career service ... At the end of the probationary service the holder of a probationary appointment shall be granted either a permanent or a regular appointment or be separated from the service."- 18 - XXIII.From these provisions, the Tribunal concludes that: 1.The granting of probationary appointments is left to the discretionary authority of the Secretary-General in the absence o f prejudice,improper motivation or any other extraneous reason. In this connection, the Tribunal recalls paragraph IV of it s