Where is the PPPoE password stored?

I connect direct to the internet using PPPoE. Works great.

Today, I purchased a wireless router so I can "share" that internet connection with my wife's laptop, etc.

So, I need to transfer the PPPoE details from my Mac's Network Preferences to the router's PPPoE settings.

Problem: I've forgotten my PPPoE password!

Solution: Does anyone know where the PPPoE password is stored?

Hint: It's not showing up in Keychain Access, for some reason, although I can access many other passwords in there.