PayPal and UPS and USPS

I have a PayPal account which is working well with Zen Cart. Great. However, if I have a customer who specifies that they want UPS shipping (and pays for it as part of their order), I go into my PayPal account and find the order and it defaults to USPS as the shipping. I was hoping that PayPal would either automatically show UPS for the shipping, or at least some note in the order would let me know which shipping method the customer wants. Can anyone enlighten me about how to tell if the order is for a UPS or a USPS shipment? Thanks a lot. I am afraid I can't figure this one out.

Perhaps I would like to ask is: it seems that the big problem is how to let me know the kind of shipping the customer wants (UPS or USPS) on their purchases. Zen Cart does not tell PayPal that. I just get the message that the customer has paid X for the product, and Y for the shipping, but how do I know what kind of shipping they want if I am offering the choice of USPS or UPS? I don't get told.

How do others handle that? How do you give your customers a choice of carrier and then alert yourself through your PayPal account as to what they want?

OR

I noticed that the receipt that I get from Zen Cart is the only place I have which tells me what kind of shipping my customer wants. Is that where you find your information about your customer's shipping preferences, or is there a way to program it into Zen Cart so that when the customer chooses their shipping method, it is conveyed to the merchant along with the PayPal receipt which lets me know that someone has bought something?

Thanks for plowing through all this.

Post number 3 is your answer. I have the invoice in hand while I print the USPS or UPS postage. Verifying the shipping address and method.

stagebrace is correct.
At the present time, PayPal doesn't allow us to tell them what shipping method was requested by the customer.
You have to rely on your order details in Zen Cart admin.