As Mauro Zarate shaped up to connect with his laser right foot, Jaidi made faces and jumped up and down in front of Howard.
The American was left flat-footed as Zarate curled the ball into Howard's top right-hand corner.
He admitted: "I saw the keeper was frustrated and I thought I could affect his concentration. It's something we used to do at Bolton - Kevin Nolan did it all the time. I learned it from him I suppose. Nolan did it a lot and we scored a lot of goals from free-kicks. It's not something I practice on the training ground, I just thought I'd give it a go."
Struggling Birmingham deserved a point while their high-flying rivals were lacklustre.
But Jaidi's actions peeved Howard, who grumbled: "I suppose it's ungentlemanly conduct, but he got away with it. If you don't catch the guy who robs a bank, he keeps the money.
"I tried to draw the referee's attention to what he was doing. I don't think referees and linesmen in the Premier League are going to have enough gumption to disallow a goal on that basis.
"They probably should do. He's in an offside position and interfering with me, but that's for the referee to make that call."
Referee Steve Bennett never looked interested in pulling up Jaidi.
Birmingham boss Alex McLeish said: "I'd like to say I told Jaidi to jump up and down in front of Howard - but I'm not that clever.
"He's a big old unit and he's not the prettiest, either, is he? Jaidi obviously did it and I don't know whether it had an effect."
Argentine striker Zarate would no doubt argue if he spoke English that his delivery was unbeatable anyway.
Even Everton midfielder Lee Carsley conceded: "It was a great free-kick and I don't think it put him off."
And Blues winger Gary McSheffrey insisted: "It was just Radhi being stupid but I don't think the keeper would have got anywhere near it anyway."