Cavalry and Infantry going into assault

[cjsiam]

I decided to play it as only the 2 new cavalry could take part in the assault, as the leader was too far away to activate the guy who was already in the hex.  It worked out fine for the Soviets, they rolled a "2" result and fried a platoon of PZIIIGs, while the Germans only rolled a "1".

The rules say that a unit in an assault hex which has NOT yet activated can join in an Assault into that hex.....
So if the Cavalry was not demoralized, and he had not activated, he would have been able to participate in the Assault when the Activated units
entered the hex.

That is pretty clear in the rules, no?
cj