Stalling CP

[miles offtarget]

I have two ATPL's etc, so I should know this; but can anyone please explain why the Centre of Pressure on a cambered aerofoil is said to move rearwards to infinity after the point of stall, when any increase in alpha below critical or stalling angle moves the CP forward ?

I was asked this over the weekend, and not wishing to highlight my ignorance too overtly, mumbled something about a stalled wing still creating some lift, and it being a mathematical expression of the physical deterioration of lift after boundary layer separation...but it didn't convince me entirely !

Thanks in advance.

Miles Offtarget