How to keep the Base Layer always at the top?

Hey there, we're currently working on this project and we're using vDesigner to let customers design their shin guards to their own liking. The problem is we would like the Base layer (the default one) to be the topmost so as to overlap any custom added text or image.
This is what it should look like

The only way to do this is to move the base layer on top of the others so that the custom layers are only seen if they're placed in the transparent area of the base layer (where the shin guard is placed).
Thanks in advance!