Date condition for sending a campaign

Hi all,

We have this flow, which should only be sent when a customer makes a purchase on today's date.

How do I set this condition? 

I tried to insert a segment with a filter but Eloqua won't let you insert it before the form.

What is the business rule we want:

Trigger the form only for customers who made a purchase on the current date.

As it is, the campaign is firing to any customer, regardless of purchase date.

I haven't found a place where I can define that the purchase date is the current one:

I appreciate any help