Fair enough I assumed since you ring the phone number mentioned in the pdf and it puts you in contact with Allianz medical team whom go through with you the pre-existing you wish to cover, ask you questions in relation to those conditions, and the extra $ you need to pay it would be the same as covering a pre-existing through a stand alone policy with them.
ie from my ANZ credit card.
Applying for cover for an existing medical condition
You can apply to Allianz Global Assistance to provide cover
for an existing medical condition(s) by contacting them on
1300 135 271 before you depart on a trip.
If Allianz Global Assistance agree to cover all or part of your
existing medical condition(s) you must pay them a $75
administration fee per person and then they will send you a
Medical Terms of Cover letter which sets out:
1. the existing medical condition we have agreed to cover;
2. the period the cover is provided for; and
3. any special conditions or exclusions which apply to
the cover.