Greig Laidlaw, Al Dickinson, Duncan Weir and Sean Lamont were the others to touch down for the hosts and 25-year-old Seymour, who has one try in four RaboDirect PRO12 outings this season, was delighted with his home international debut.
"I'd like to think the supporters can come away from here and hope for the future looking bright," he said. "We've gone on the attack and scored some points so that's positive.
"It's great to finally get out here at Murrayfield and play a game.
"To get two tries is really special for me. My parents were in the stand and they haven't been able to watch me play for a little while.
"There are parts of the game we're not too happy with, and a couple of those things personally, as well, didn't go the way I'd want them to but I'm not going to complain.
"We've got to look at it as one step at a time. We're building towards something, which is the World Cup in 2015."