Expertise in CRE is not hard to find at most Insurance companies - they account for a large chunk of the commercial mortgage lending market themselves and have seasoned real estate staffs (mostly).
Typical CMBS investment - AAA 30% subordinated CMBS. Why? Its 10-years long and bullet proof. They want something that will be there in 10 years (or longer) so they can use it to pay off insured payouts.