Is it possible to add additional address to an IMAP account?

[WPCentral Question]

Change From adress in MetroMail

I've installed MetroMail to get support for mail aliases (Multiple From adresses). It stated support for multiple From adresses in GMail. I don't use gmail, but have another provider, which supports multiple mail aliases. Is there a possibility to add additional from adresses to a IMAP account?