I am trying to book SIN-DRW-DIL with BA Avios.

Problem 1: ba.com does not recognize the DIL airport code. Are there any online workarounds? Iberia and Qatar Avios search pages also fail to recognize that code.

Problem 2: I phoned up Executive Club and spoke with a very pleasant and helpful agent, but the best they could do was price the two segments individually.

SIN-DRW 13k + $73.40 tax
(forced 8hr 45 min layover)

DRW-DIL 6k + $87.20 tax

Obviously I don't mind paying taxes due, but it is frustrating that they won't ticket it as one ticket. Given the distances involved, the total price should be 13k. The agent said it might be related to the fact that the flights are operated by subsidiary airlines, but I'm not sure I buy that story as they carry prime QF flight numbers (QF282 and QF351)

I'm curious if anyone here as suggestions. I don't mind a bit more HUACA.