Sub-2 Lender Ltr and Insurance

I’ve read a lot about getting on the sellers insurance policy when doing a sub-2. My question is when the seller has let their policy lapse; the lender then uses their own insurance to protect their assets. In this case, Countrywide is the lender and is using an in house insurance group from what I can tell. How do I get on that policy w/o tipping off the DOS?
Secondly, I’m looking for a sample letter that I can send to lenders informing them I am now “managing” the property and all future bills and correspondences will now come to me. I didn’t want to reinvent the wheel or possibly triggering the DOS with a letter not properly worded. I look forward to the replies.

Thank you,
OnTheSpot