Second conditional ? would or should ?

Please first look at this question.

When she couldn't find any, she kindly filled out a form requesting the item be held for me ______ the store receive another shipment. I was very impressed by Ms.Warren's willingness to help.
(1)would (2) should

The correct answer is "(2)should. I have two things to ask you in the sentence.
First, for the verb of "request", the writer used it as a causative verb like the verbs of "get" and "have". It requests the item be held for me. Am I right ?
Secondly, the questioner didn't write as "the store receives" ,and just wrote as "receive" as its infinitive. I could easily catch there is no "Auxiliary verb" ,which means the clause that the store another shipment concluded into a second conditional. Then, where is the main clause ? and why can't I use "would" there ? If the store would receive another shipment. If the store should receive another shipment. I think there is no big gap in the meanings.

Couldn't you help me a little bit with understanding this question ?