I don't know if this helps. The "key" is embedded, so is automatically used during the instalatin. There is still a requirement to activate it though. I do not need to use the trial so cannot say, but normally there is, under the activation panel, an option to type in a new key, and then reactivate. If that exists in the trial, you may (although I doubt it) be able to insert the new key. A partner key woul be the same as a Technet key. The product is supposed to be for test purposes and you can reactivate indefinitely, but should not use the product as you principal OS. Of couse, Microsoft would not have too many means of determining if that is what you intended.