Your concern implicates the exceptions:G1.64 -
1.64 CC: Whenever ≥ one unbroken Japanese Infantry/Cavalry unit is the ATTACKER in CC/Melee or Ambushes the enemy in CC, that CC/Melee
automatically becomes Hand-to-Hand (J2.31) unless every such Japanese unit participating in it was
Ambushed in that phase and/or is Withdrawing/pinned.
The rule stating that the HTH does not apply to the attack on the vehicle does not override the rule that the CC/Melee is automatically HTH. I found a PS about a sequential CC involving voluntary HTH in VOTG. I don't think it helps.However, Hand-to-Hand CC can never be used by/vs any vehicle(s)/PRC/pillbox-occupant(s).