Add strawberries to a Fondant cake?

Okay so ive been trying to fill my fondant cake with strawberries. First I'll layer the cake with buttercream, then lay out sliced strawberries and put on the second layer of cake.. this seems to work for a short amout of time unil the berries start dripping or like turning into ooze. which ruins my cake inside under the fondant.. um what do I do? can I maybe freeze the strawberries then layer them on the buttercream? that way it will hold for longer?