Problems with residence permit due to health insurance coverage letter

Hello my fellow expats.
We need your help. We just moved from beautiful New England, USA, to Salzburg and are encountering problems obtaining a residence card and permit, because the Austrian government will not accept our international health insurance and the visa letter. How did my fellow expats solve this problem?

We retired from the US government and moved to Salzburg, where we own an apartment. We have enough income to sustain us, and my wife, a german citizen, owns an apartment.  We did extensive research to find an international health insurance that would cover me for the first year and my wife for the first 6 months until we qualify for the social health insurance.  Both insurances provided visa letters.

But the official at the immigration office does not recognize them. He gave us a list of insurance companies, all Austrian, that are officially approved and would give the same coverage as the Austrian social health insurance.

I bought a plan that actually covers more than the social health insurance from Geo Blue, but the insurance refuses to sign the official certification letter required by the Bezirkshauptmannschaft.  My wife just bought a basic travel insurance to tie her over until she is covered by the Gesetzliche Krankenversicherung.

Without a health insurance certification I cannot get my residence permit, even though I am married to an EU citizen.  And even my wife will have to show a valid health insurance certification according to the government official.

How did you all handle that?
What insurance did you choose?
If you chose private insurance what was the minimum contract term?
What travel insurance did you chose?
Has anybody ehad similar experiences?

I would really appreciate any advice.  The health insurance issue is an unwelcome surprise and obstacle.
Thank you