Composite on pre-cast concrete step??

I have a client (condo management company) Edmonton area who wishes to cover their pre-cast concrete steps with a composite ("trex" or "azek"). I have never done such a project nor can I find anyone who has. Cannot fasten to concrete with screws without obvious gaps, nor can I rely on a "PL" type product to adhere with confidence. I have inquired with the manufacturers of these products and no response.

These condo units are fully finished (30 yrs now) fenced etc... the landscape does not allow heavy equipment to access these steps to pull and reinstall as per norm. I have found a contractor who manufacturs fiberglass molds to go over but but it does not have a satisfactory finish once installed. The only thing I have come up with is to smash out the extisting concrete pre-cast and build a wooden deck like landing and stairs. Many of these units have been salted to death and are extrememly rotted in a few cases the concrete has failed right through (open voids).

Any ideas out there??

thanks in advance.