I see you need a "3rd party employee" plan to get a rep to make the modification. And even then, the Rep would NOT being following protocol precisely by making this mod for you so it will be hit or miss depending on the Rep. This plan needs to be like a corp. employer plan (i.e. plan when you worked at Best Buy, Sprint Store, Radio Shack, etc.). Plus you have to actually HAVE the EVO in hand to give them the ESN. This is a risk if you can't get it done and then you have the phone that wont work on your plan.
It appears this Indirect Demo modification technique only works with this unique type of plan. SERO users are still SOL.