Create Scheduled Tickets from Date Attribute

Greetings,

We would like to create Scheduled tickets based off of a custom attribute on a few of our Configuration Item fields.   For instance we have a Configuration Item for Applications where I would like to have a scheduled ticket created 6 months prior to the application's support contract expiration date (Support Contract Expiration is the custom field on the CI Record).   We presumed that would scheduling based off of a recorded date would be quick and simple however when we look at our scheduled tasks it appears to only have the ability to be based off of static Calendar Year constructs (Yearly, Monthly, Weekly, Daily).

Your guidance and support would be appreciated...Even if we are going down the wrong path trying to use a Scheduled Ticket.

Thank you.