it get's a bit lost in the first moment but it's actually pointed out on the frontpage (just remembered that the yaamp software used to have this feature):
Non-BTC payouts depend on that coin being mined as your BTC balance is traded internally by our system to your currency of choice. If we have not or are not mining that currency your payouts will be delayed until the pool has mined the blocks for you to get paid. If you notice in the pools status that the currency is red, it means there is not sufficient amount of the currency to pay miner(s). It's recommended to use BTC.
Use -p "c=SYMBOL" if zpool does not recognize the currency correctly.
See the "Pool Status" area on the right for PORT numbers. Algorithms without associated coins are disabled.
so, no direct port to mine amber, just x13 (or multi or selected algos)... but payout in amber... I'd susspect this to be even more efficient than mining directly...
btw nice work, the new zpool, will certainly take a ride in near future
xpool certainly belongs to the multipools (and zpool I suppose soon will) most dreaded by the profit searching solo miner , as they both seem to be not only very well cared for but also thoroughly optimized and tuned for maximimum profit. however, stricly speaking I can only share this experience for xpool, 'cos zpool's quite too new, but I've got that certain notion...
should be another nice contributionl to ambercoin market capacity and demand