I agree with Russ, so far the dicor caulking I have used has been ok.
I put some kinda rubber stuff on the outter wrap of my awning and it has been flexing every time I unroll and roll up my awning and it has not yet flaked in any way, nor has it seemed to effect it in any way. (so far)
but what I noticed is according to the amount that I should have used? I ended up with extra which told me I did not get as much on it as I should have and I thought I had worked a extream amount on it, so make sure ya figure out a area to what amount it calls for.