Resealing door membrane - which sealant?

[E55BOF]

Good afternoon, gentlemen. I need to replace the (missing) plastic waterproof door membrane on my R129. Polythene builders' sheeting is not a problem for the membrane, but I've no idea which sealant to use to stick it in place. Does anybody have a recommendation?

 

[markjay]

In the past I used RTV, e.g.:

Sealants : Permatex® Clear RTV Silicone Adhesive Sealant

It worked fine but I am not sure if this is the 'official' product for this purpose. The original adhesive was mastic-like and resembled grey-coloured Blu-Tack...

 

[E55BOF]

Thank you for that; I don't care if it's the 'official' stuff, so long as it works.