Waldron Model Products makes 1/24 Luftwaffe rudder pedals (theirs come stamped in metal, no folding required, they’re already 3-D), German harness buckles, and film instrument faces for WWII German a/c. They also make a cockpit placard/PE set for the 1/24 FW-190. I don’t know if much of it will cross over to 109, but I doubt enough to justify price. Best of luck on the build.
MDC and Eduard also make seatbelts for the 109 E; you can also find Cutting Edge and E-Z Masks… masks; you could take a look at Large Scale Planes site : http://www.largescaleplanes.com