So what does the aircraft need to meet PBN Regulations?
If it needs WAAS GPS units, then look into the costs associated with doing a mod or STC and go get it certified.
Or, ask Leonardo to do it for you at your cost. They will then issue a Service Bulletin specific to your helicopter.
If and only if they think there is a business case, then they will pay the costs and issue a Service Bulletin that anyone can install.
PM me the details of where you are, which machine and who you contacted and I'll see if I can get a better contact and clearer answer for you.