FatWire Engage - how to create a segment that can compare on Date

I am posting this question for a colleague who does not have access to the Support Community.  This question was submitted as a support ticket, but they said there was no out-of-the-box functionality to do this.  They suggested posting the question to this community.

We are setting up FatWire Engage and are trying to create a segment which can do a comparison based on Date.

We want to show some content to users (on login) whose account membership will expire in 45 days - i.e., we need to create a segment that can make a check as follows:

user_account_expiration_date < today + 45 (days)