Hi, Salmat!
I’m fairly certain it would work perfectly well, because it is thick enough to keep the mousseline from breaking down. However, strawberry jam is very sweet, and its falvor is often not as “strawaberry-y” once it is diluted. If you don’t mind a milder strawberry flavor, and if you don’t mind a sweeter frosting (and many don’t), this should work very well for you. Because of its thickness, you can probably put in more jam than puree, but if you add extra, do it slowly so you can taste it for sweeness and watch the texture.
If you have freeze-dried strawberries in your store, you can powder them and punch-up the flavor. I made strawberry mousseline using powdered freeze dried strawberries (the crunchy kind), and it was not only delicous on the cake, but it was quite amazing on graham crackers…. (http://www.realbakingwithrose.com/index_ee.php/forums/viewthread/3627/)
Good luck!!
—ak