I did this once in 13 years but I seem to remember that the valance has to be removed. look up under them and you will probably find at least one phillips head screws holding the valance to brackets that will require a long screwdriver bit to remove. Testing my memory.
Dick_B
2003 SunnyBrook 27FKS
2011 3/4 T Chevrolet Suburban
Equal-i-zer Hitch
One wife, two electric bikes (both Currie Tech Path+ models)