I made the jump a few years ago when working in Geneva.
One thing that really helped me was my old 1st school year knowledge of Unix, C and basically anything 20+ years old. They have a lot of systems that rely on as400, Shell/AWK scripts and jobs, Cobol and all this stuff. They are so afraid to break it that they never change it.
Also, be good about security. Know what SSL is, encryption, DMZ, anything related to data security, redundancy and hacking. Banks hate security breach and are very serious about it.
Make sure you refresh your memory about these two points and it will help a lot.
Good luck !