As far as the 1 year restriction, I heared that all over this forum. I do not know from experience. I do not buy products from serious under-cutters like that. There is usually a catch ( as you hve found) and undercutters like that should be damned to a life of selling to cheapskate "buyers" on ebay who want it all for a penny and no shipping and then leave bad feedback when it arives one day later than they expected, IMO.
As far as pushing, Ithink the best way to do it is to open up a new yahoo account, buy the domain, sell it, then jsut hand the account over to your buyer. he can then change the password so you can no longer access it. Since you probably bought the domain under your main account, this may not be possible anymore. Oh well, live and learn. Never buy anything based on price alone. that is a recipe for disaster, as many buyers find out everyday. I too found out the hard way when I registered my domains with registerfly.com. they totally hosed me and took my domains from me. the only reason why they got away with it is becasue I have no time or money to pursue it legally (not yet anyhow, I still have time). And they would lose the case for sure as I did nothing to merit it.
If you do a little browsing in this section you will find many threads that answer your question, I believe.
I said it before and I will say it again...
You get what you pay for. In Yahoo's case, you get nearly nothing. It's almost as if you really don't own the domain. In regfly's case, you get a domain along with high blood pressure and frustration. ANd then eventually, you might find that they just yank your domains from you and sell the better ones at a premium price to a trader. I have had this done to me and I am not hapy about it.
However, I do believe in karma. Hell, my name is Karma.