McCoist held talks with the centre-half at Murray Park on Sunday in the wake of his ordering-off in the pre-season friendly against Derby County.
The French-Tunisian player's volatile nature got the better of him again at Pride Park and he aimed a flying headbutt at opposing striker Chris Martin.
The red card he received for his violent conduct has earned him a two-game ban after the SFA received a report from referee Mark Heywood
That rules him out of the Petrofac Training Cup game with Hibs at Ibrox tonight and the first league game of the season against Hearts on Sunday.
And McCoist is concerned about teams in the SPFL Championship deliberately trying to antagonise him in the season ahead due to his suspect temperament.
"I have told Bilel myself that if I was the opposition manager I would try to wind him up," he said. "That is definitely what I would do.
"I sat down with him on Sunday and watched the incident in the Derby game again. I could see that Martin fouled him. But in no way, shape or form can you react in the way that he did.
"It is just a switch. And it is something that he has had throughout his career. He knows he would be a far better player if he could get rid of it. We all know that.
"Whether he counts to 10 or walks away, he is going to have to learn. It is just something that he is going to have to do.
"We have obviously spoken to him on numerous occasions, including before we signed him. But, as I say, you don't see it until the switch goes."
McCoist added: "That is the third time he has been sent off for us. I have got to say, the second one against Brechin you couldn't defend.
"But I thought he was very unlucky to be sent off the first time round against Airdrie.
"Then again, Bilel fell for players trying to goad him in that game.
"But the other two were just flashes where he lost it. It is just something that we and him have to work on and try to eradicate. I had a good chat with him yesterday.
"He knows it was totally unacceptable. He knows he was wrong. He let himself down and let his team-mates down. The upsetting thing is he is a really nice boy, helpful, great with the kids, great with the supporters.
"But there is that wee flaw within him. If he is available for selection then he will certainly come into our plans and thoughts."
McCoist strengthened his squad with two new centre-backs during the summer - Darren McGregor and Marius Zaliukas.
And Mohsni, who was the second-top scorer at Rangers last season with 12 goals, faces a battle for a regular first-team start this season.However, his manager has stressed the 27-year-old fans' favourite will still feature prominently in his plans for the 2014/15 campaign.
McCoist said: "I don't think at this time that we are in a position to get rid of players who will definitely be big parts of our season unless there is an automatic replacement who is better.
"We speak about the downside of Bilel, but he and Lee McCulloch scored in the region of 30 goals for us and that's from central defence, so it's a reasonable return for your centre-halves.
"He has a problem but it is one we're working to resolve.
"What I do know is that he knows he was wrong and he accepts totally that he let the boys down."
Meanwhile, McCoist has stressed Rangers are keen to win the Petrofac Training Cup this season, despite the Championship title being their top priority.
The Ibrox club suffered one of the most painful defeats in their history when they lost 1-0 to Raith Rovers in the Ramsdens Cup final at Easter Road back in April.
And their manager is keen to atone for that loss this term even though winning promotion and completing "The Journey" back to the top flight is their main objective.
He said: "We want to do well in every cup competition. Last year's final against Raith was a disappointment.
"In that game we created enough chances to win but didn't play well enough.
"That was a major disappointment because the club wants to do well in every cup competition.
"We want to win it but we need to get out the division. That is the most important thing once again this season.
"That said, a cup run gives everybody confidence and everybody a nice day out at the final for the teams who get there and that's what we want to achieve."