There is an older trick to force the machine to print long itineraries, though IIRC, it was only possible with BA/QF/AY/IB (the Amadeus based carriers):

First they'd issue the first half (or 15-segments) of the itinerery, then an open-return to origin. The taxes would calculate only for the 16-segments included on the ticket.

Then, they'd exchange the last coupon (coupon 16) for the remaining five flights (or twelve, as was my case before the 20-segment limit was introduced). The additional taxes would be listed as an ADD/COLLECT.

It's a slight pain the ... to calcualte all the taxes twice, but it's a lot less trouble than writing coupons by hand.

Not sure if this will work with Sabre though.

Why don't you ticket the thing through AA or CX in Pakistan? Maybe its a bit more expensive on the tax-front, but it will certainly be a lot less trouble.

Good luck,

Checkerboard.