lesser metamagic rods on metamagiced spells

There was information somewhere that a lesser metamagic rod could be used on up to 3rd level spells that are under regular metamagic effects from the caster. Can anyone show me where this information is? I cant remember if it was a question, answer, form post. I just remember having read it. Came up in todays game and wanted to provide the information to the group.

So for example, a wizard could use a lesser metamagic rod of empower on a maximized fireball.