Steps to Reproduce:
1. Launch JIRA 4.0/JAC(using bamboo build 139 Trunk)
2. Login as any user.
3. Create a issue and try to attach a filename having $(at the time of creation) sign in it. The file get attached and no issues.
4. Open the already created issue and then click on "Attach file". Try attaching the same file.

Result:
1. It give the same error message " The filename of the file contains an invalid character: $

• No files were attached. Please add your attachments again (lost during reload)."

Expected:
1. User should be allowed to attach the file with out any issues

Additional Info:
1. Nanako in finance regularly uses this functionality(all the files have $ character).