Not sure if you got an owners manual with yours but I just looked at the manual that came with my new 2012 X19H. Canvas maintenance starts on page 65. On page 66 it says for mild stains, dirt etc use mild liquid detergent and water using a sponge or soft cloth. It says for more stubborn stains the tent fabric OEM recommends: oxiclean, fantastick (must say it can be used on vinyl), star brite vinyl cleaner/shampoo #80216, Meguiar's 57 vinyl & rubber cleaner/conditioner #5716 and there are a couple more I don't have enough time to write (sorry but I'm off to drop the wife off at work)...
2012 Jayco X19H
2012 Ford F150 Ecoboost w/ max tow, 4 door w/ 6.5 ft box, 3.73 gears.