Help with Matching

When I download a bank statement from my bank, the file name has the following format:
9digitaccountnumber-ddmmmyyyy.pdf which looks like
123456789-20Jul2012.pdf
What I want to do is rename this file to be
9digitacountnumber yyyy-mm-dd.pdf so it looks like
123456789 2012-07-20.pdf
I have read the using match patterns section of the help menu but I am a little stumped about how I can do this??
ETA: With more fiddling, I have defined custom tokens for the year, month and day and can rearrange them in the renaming so I can get from 20Jul2012 to 2012-Jul-20. But how can I turn 'Jul' into 07 (or whatever month it is)?
ETA (again): OK I think I've worked it out - when I rename, I tell the custom token for the month to replace the text Jul with 07. I have put in 12 such replacements, one for each month.
This 'seems' to be working.
I apologise if this post is a really dumb question. I won't delete it in case it helps someone else but if you think its not that useful, then just delete it.
I have no experience with programming, apple script etc and so working out these rules is a whole new world for me.....
9digitaccountnumber-ddmmmyyyy.pdf which looks like
123456789-20Jul2012.pdf
What I want to do is rename this file to be
9digitacountnumber yyyy-mm-dd.pdf so it looks like
123456789 2012-07-20.pdf
I have read the using match patterns section of the help menu but I am a little stumped about how I can do this??
ETA: With more fiddling, I have defined custom tokens for the year, month and day and can rearrange them in the renaming so I can get from 20Jul2012 to 2012-Jul-20. But how can I turn 'Jul' into 07 (or whatever month it is)?
ETA (again): OK I think I've worked it out - when I rename, I tell the custom token for the month to replace the text Jul with 07. I have put in 12 such replacements, one for each month.
This 'seems' to be working.
I apologise if this post is a really dumb question. I won't delete it in case it helps someone else but if you think its not that useful, then just delete it.
I have no experience with programming, apple script etc and so working out these rules is a whole new world for me.....
