You mean the lower right,horizontal corrugated hose, not the vertical rubber hose?
If it is just the clip on one side and not the entire fitting, the plastic zip tie idea is great imho.As the corrugated hose ages, it becomes very stiff. So if you managed to get it back on and fully seated, with one clip working - use the zip tie. There is very little movement there. If the corrugated hose is very stiff, the next mode of failure is cracking in the base of the corrugations. Suggest you plan on that -sorry. I have just done that job, have the grazes to prove it. I have no idea how people with big hands do it. It is hard enough with the gearbox out and the car on a lift.
We really need some long-term results on Stelan's alternative to the AOS. I have vowed that the next time I do this job, it must be to upgrade to a more mechanic-friendly design.See Post 11 in the link below for more details and a link to a detailed dwg.
http://986forum.com/forums/diy-project-guides/63598-making-better-air-oil-separator.html