I'm looking for a travel agent who can ticket infant fare(s) for me. I'm told a 'good' travel agent is required.

E.G I have a requirement to book an 'infant in arms' ticket for an itinerary where the infant will have it's own (separate) purchased seat for one of the legs - meaning that I cannot book through the airline.

on another itinerary there are many domestic legs which would be free, but booking through the airline will result in a price of 10% of the entire (complex and expensive) itinerary.

I'm hoping that a travel agent will be able to sort this out and simply book what I need

examples of the sort of tickets I'm looking for are as follows
LHR-MEL on QF9, in First, one infant fare point-to-point.
SYD-FRA on OZ via ICN in Biz , again point-to-point infant fare not including the rest of the (award) itinerary is needed.