http://www.vietnamgear.com/dictionary/trim.aspx
http://www.usmilitariaforum.com/forums/index.php?/topic/201071-please-help-identify-a-patch-trim-vietnam/
"the Training Relations and Instruction Mission (TRIM) went into operation on February 12, 1955 and was deactivated on April 28, 1956, when the French withdrew their advisors. This joint Franco-American unit included only 33 US and 28 French officers and enlisted men."
=>en clair,cadres militaires US et Français pour former l'ARVN,avec des résultats plus que mitigés.