翻译这句话，翻得好的话我会追加悬奖分

our usual way of payment is by confirmed and irrevocable letter of credit available by draft at sight for the full amount of the contracted goods to be established in our favour through a bank acceptable to the sellers.

我们的一般付款方式是保兑的、不可撤销的、以我公司为受益人的、足额信用证，见票即付。信用证应通过为卖方认可的银行开出。

Concerning pay the condition, we usually request to protect the 允 , can't cancel of, with the letter of credit that demand draft pay.

About the condition of payment, we usually request to guaranteepermit, cannot be abolished, depends on the demand draft payment theletter of credit.