its gunna be hard, you'll have to take the 2 pipes and then weld cross bars set at just the right depth to keep the lexan up and flush with the two pipes running the whole distance (id say every 6 inches or so apart).  Then every 4 to 6 feet make a stronger cross bar that will hold up your legs, then there is probly a whole lot of other things involved that im not thinking of but if you can do it it would be sick, just really hard. good luck