Here is the address to IHI Buja
www.ihi.com They cover US and international travel. Check out the Annual Travel section. They have a coverage list.
I believe they will cover the cost of getting you off the mounatin (i.e., mule, helicopter) but I do not know how they handle if there is not a system already in place. You can send them an e-mail and ask.
I noticed they are offerring a 5% discount on Annual Travel insurance.