It was the Chelsea loanee's fourth goal since joining the Saddlers in the summer and, with his spell due to expire on January 4, Smith is keen to keep the 21-year-old for the rest of the season.
"We are speaking to Chelsea at this moment, but nothing has been finalised," he said. "We are hoping to keep him.
"His goal was a great finish and he had another couple of chances. Milan was a bit sloppy in the first 20 minutes and his selection - when to go and when to pass - is something he needs to work on.
"I don't think we were at our best but we got away with it, and Carlisle's penalty miss helped."
Walsall took the lead through Romaine Sawyers' fifth goal of the season in the 14th minute.
Carlisle should have been level after 25 minutes when Andy Taylor's hand struck the ball as he slid into a tackle. But Saddlers 'keeper Richard O'Donnell blocked Lee Miller's penalty, and when the ball rebounded to the striker with the goal gaping, he thumped it over the crossbar from about three yards.
The Cumbrians paid for that when Lalkovic turned quickly on the corner of the box and scored the second for Walsall with a flashing drive which went in off a post.
Lalkovic said: "Everybody knows I want to stay here longer and I think they (the clubs) will agree. I am enjoying it here and hopefully can stay till the end of the season."