Well ... In lieu of an accredited expert Ill throw in my twopenorth.

Id suggest that you get your company to treat it as they would any other hydraulic ram and certificate it to a working pressure of 150 bar ... It would then become a standard ram.

This should result in a ram that ( when its derated by 50%* ) should easily meet the FRA rules.

* If you take an unmodified standard hydraulic ram, you can use it on pneumatics to a pressure level of 50% of the rams hydraulic rating or 1000 psi - which ever is the lower without requiring further test certification

Im working on the assumption that Pauls hydraulic rating is refering to working pressure as opposed to test pressure.