Proof of Missionary Service?

A member in my ward is applying for board certification in his field of expertise. His application requires that he provide documentation proving his residence for the last 10 years. He has asked me, as ward clerk, if I can provide him with a certificate or form of some sort which will provide documentation of his two years of mission service.

Is there something I can access within MLS to help him? If not, where can I direct him to get some sort of official proof of missionary service? Any help is greatly appreciated.

His release certificate or call letter might help. MLS is not going to have his years of service as a missionary. Otherwise, the Missionary Department might be able to help.