being not prior to the date of delivery.

22:28 May 12, 2014 

沒有because, since, as的意思。BEING 只是伴隨狀況，或者現在分詞作定語，=WHICH IS

10:06 May 12, 2014 

这是一个 being clause, being = because, since, as 的含义。

‘being’ in participle clauses

We can use an adverbial participle clause to express reason or cause as an alternative to a because/since/as clause. Using a participle clause in this way is more characteristic of written English or a literary style, rather than spoken colloquial English.

例句：Being rather over weight, Geoffrey was unable to squeeze through.

因为／由于 Geoffrey 有一点过胖，他无法挤过去。

而无须写成

Because he's rather over weight, Geoffrey was unable to squeeze through。

BBC 英文学习网页有这样的教导：
http://www.bbc.co.uk/worldservice/learningenglish/grammar/le...

原文有用 being 的相同表达方式：
... time of payment shall be 60 (SIXTY) days from the receipt of the invoice, being not prior to the date of delivery.

这样理解较容易：

由于无须在交货日期前付款，所以必须在收到发票的 60 天内支付。

shall be ＝ 必须 （法律用词）

基于以上的理解，个人相信 prior to date of delivery 是指 payment，和 receipt of the invoice 无关，而且是很重要的焦点。

供讨论。

22:15 May 11, 2014 

写错了，还是指收到发票的日期不早于交货时间。