You should be able to set up a static email signature in each account's settings. I suspect it may become a little confused if you reply from within the Local Folders account; it will likely use the signature associated with Thunderbird's default account. It also messes up, I read, when you use ''Reply All''. I use [http://mozext.achimonline.de/signatureswitch_about.php Signature Switch]. Look out for additional features like hybrid sigs, so you can have both plain text and html formatted signatures in one file. It can also choose a signature dependent on recipients/addressees rather than just the account being used when creating the message. Some users prefer a clipboard-like tool such as QuickText or Clippings.