Thrower Commits Foul

[Fritz]

First time I ever saw this and wanted to confirm the correct call:

BJV, A1 has the ball on the end-line for a spot throw-in. B1 is guarding the throw-in but is not violating the plane, just frantically waving his arms. A1, with the ball cradled in one hand, reaches thru the plane with his other hand and shoves B1 in the chest, knocking B1 back a step (no, I have no idea why, A1 had plenty of room to back up). I am administering the throw-in and call the foul. Report it and we have a throw-in for B at the same spot (very early in the game, no bonus situation).

No arguments from A's coach other than to ask me what happened. When I explained, he said "first time I've ever seen that happen; ok then." During the next timeout though, B coach suggested that should have been an intentional personal foul since that is the call if the opponent reaches thru and fouls the thrower. But he wasn't really arguing or asking for an explanation and went right into his team timeout.

Well, my partner agreed with my call and I couldn't find anything in the rule or case book about this kind of situation other than the thrower is allowed to reach thru the plane, with or without the ball, without that act being a violation.

Was I correct or should this have been an intentional personal foul?