mining proxy need setworkaux so i think 1) will be ok ?
so why in first scenario i get errors on client miner ?
The only supported scenario is:
client miner <--> eloipool <--> bitcoind
|-> mining proxy <--> namecoind
you mean
client miner <----> eloipool <-----> mining proxy <----> bitcoind
|
| ----> namecond
so i must use patched bitcoind (with setworkaux function) ?
or maybe
client miner <----> eloipool <-----> mining proxy <----> eloipool <--- > bitcoind
|
| ----> namecond
?

No, I meant exactly what I said...