with my legend i use just a length of rubber hose that simply slips over the exhaust its a heavy duty steel reinforced hose i got it from a local supplier. it's approx 1 meter in length and with the natural curve i can deflect the exhaust left, right or straight down under the van what ever suits depending on the location, relative to the entrance to the job.
I learnt the hard way early, I set up for a job and the exhaust was blowing straight into the open door way of the apartments i was cleaning, set all the fire alarms off in the building and found out that the local fire department didn't have a sense of humour.