That's a fantastic western custom, playmobueb!
If this is one of your simpler customs, I think we're in for a treat with the rest of Sweetwater. It's great to see some Western enthusiasts and customs on this site!
I recently purchased this Sheriff's office and am using it for its intended purpose, but I didn't fully realize its possibilities as a bank as you did. It certainly looks secure with its stone and bars and safe! I am using the older grey clapboard with green trim Sheriff's Office as my town bank along with the bars that came with the set and the safe you pictured. It works okay with the bars and the boarded and barred window, but the clapboard is certainly no fortress, unlike your bank! I think this safe works okay in the Western theme, although not perfect as it is modern and somewhat colorful. It looks better in your bank with the blue window trim. I wish Playmobil would make a nice black, burgundy, or forrest green old fashioned safe with gold trim. Maybe that's planned for the hopefully upcoming "El Paso" Western theme.