Configuration of P1 versus INT0 !

I want to use the external interupt pin 0.
So I configured the Port 1 like this :
// 3 IRQ : Input Only.

But when debugging, the checkboxes in P1 window are greied for P1.2 and P1.3. All these bits are set. So it gives P1.3 in pull-down mode :
P1M1 = 0X7E;
P1M2 = 0xAD;
It's not the mode I wanted !
Is there an option somewhere that inhibits these checkboxes ?
How could I make the INT0 to be effective ?
Thanks.