STR9 interrupt handling information

Hi, I'm quite confused about some interrupt handling issues on STR9. In http://www.keil.com/support/docs/3248.htm, technical support suggests this: "You must acknowledge both VIC at the end of each interrupt function". However, AN2593 STR91x interrupt management, at point 3 of Vectored handling of IRQ interrupts (pag 6/15), says:

"After finishing the interrupt processing including the clearing of the interrupt flags, you must write any value in the VIC0 vector address register if the interrupt originates from VIC0, or in the VIC1 vector address register if the interrupt is from VIC1, this in order to indicate to the VIC that interrupt processing has finished, so it can update the priority logic: then a same or lower level interrupt will be able to interrupt the CPU."

I find it a bit contradictory, could somebody clarify this?

Regards,
Gaston