How to use imap_open for a proxy?

Question

I really don’t know how to ask this question, so I’ll just ask it as best as possible. Is it possible to use a proxy connection to read mail from pop3 or an imap server using PHP imap_open ?

I would prefer to use imap_open as it is so simple to handle mail. but if using imap_open not possible, then what other solutions exist? Can fsockopen or fsockopen work? I cannot find any example showing a connection to pop3 / imap behind a proxy server in PHP.

Any advice would be very helpful!