Had a chance to look at some of those pics in the link and it seems to me that you can go to the hwd store/Home Depot and pick up a L bracket/shelf bracket or even some aluminum stock depending on your requirements and with the help of a hack saw and drill - - - AND proper location - - - you could bolt them inside at the necessary location and "Voila".
There are many options such as
Shelf or L brackets that come in many lengths
IMG_0030.JPG
Just straight stock that you can bend to your specs
IMG_0032.JPG
Or cut off some angle iron, drill holes and mount if it will reach far enuff to hold the water pan.
IMG_0031.JPG