Ladies and gentlemen, finally, I think I have the resolution:
After trying all the previous ideas, I discovered that when I was connected to my wi-fi trying airplay, the "iphone" option wasn't offered, just dock station, apple-TV, and other airports that I have in my network...
Other situation like random playing music like 5 seconds after deploying from dock etc told me that the problem was in the dock connector at the button of the iphone.
So I turned it off, took a Johnson cotton swabs with alcohol little wet... I passed it several times into the iphone dock connector.... then another but dry... both start be something dark, dirty... so i waited until the iphone connector was dry and turned it on....
that occurred an hour ago... since that I´m hearing my music on my iphone speaker!!! good luck!!
Pl advice if it worked!
Appologies for my english!
TRITRO