help with kicking horse

["guest@endurance.net" <guest@endurance.net>]

Vicki Wheeler dwheeler@icx.net
I'm posting for a friend without Internet access, so bear with me while I try to get this right.

She has a new horse (approx 11yo Arab gelding) that did his first 50 last weekend.  She started late & was going 
at a 5-6 mph pace.  It didn't take long before the 25 mile leaders caught up & sped past.  Storm kicked out (yes,
he was wearing a red ribbon) & dumped her.  Thankfully he returned to the scene & they completed.  He has cow-
kicked before (reason for ribbon) but never this violently.  Monday night she went out to check on the horses (4 
geldings turned out together) & the herd leader was chasing Storm around the field with ears flat & teeth barred.  
Storm was kicking at Star to ward off the attacks.

She knew the horses didn't like each other but she didn't realize it was this bad.  She doesn't have the space to 
separate the horses &, obviously, Storm will continue to kick Star when attacked like this.  She believes (& it seems 
viable to me) that Storm was reacting to the horses running up behind him as if Star were running/attacking him.

Now for the question -- how does she train Storm not to kick when there is a rider on him?  I've never had a kicker so 
I'm lost here.

TIA for all tips/suggestions.
Vicki Wheeler
Knoxville, TN