Hi Alex
I have no other experience in SAP other than MM, WM and a little PM. I moved into security purely to support a UK Gas company during a rollout in 1999.
I openly admit to not having any proper portal etc expertise but I still consider myself to be a half-decent SAP security contractor in the ECC environment.
I have no certificates from SAP (unless you count a procurement one ) but I think I can generally get by in my daily tasks.
Most important thing is (IMO) - working in your team and sharing/working together to understand issue and resolve them.
If you have good selection of people in the team then you are 'cooking' techie, programmer, portals, business knowledge, security
Maybe I'll pick up the new stuff as I bimbles along but I tend to forget the old stuff as the new stuff takes its place. Used to remember where I lived once I think...
Best wishes
David