Thank you for your question. Unfortunately, JA does not provide / have experts which provide notarial services.
However, I would like to suggest two approaches:
1. Using a local German notary public, which you can find by searching this site: http://www.notar.de/
They can authenticate the document required, or simply attest the signature (which is cheaper and equivalent to US notarization), and then you must obtain the Apostille (from the local court of where the notary works). This will make the document valid for the US;
2. Using one of the two new services provided by Commonwealth of Virginia companies. Virginia passed a revolutionary notary law which allows long-range notarization with bank-grade security. The documents are deemed to have been notarized in Virginia directly. See the top two companies here: https://www.notarycam.com/ and here: https://notarize.com/
I am not affiliated with them in any way. Note that the 2nd option does not require an Apostille to be used in the US, and the document can be shipped to the legal adviser / house owner in Florida directly.
I hope my answer was useful and look forward to your rating, which is essential to my activity.
Dr I L Vlad