Using Personalization to Control Access / Behavior in Control Purchase Requisition form.

I've made several attempts at this to no avail so I'm turing to the community for guidance. 

Basic Requirement:  Restrict the ability to Cancel / Finally Close Requisitions based upon the Attribute Category of the Requisition Header.

Approach thus far:  I've used Forms Personalization on previous projects so it was my natural tendency to use this approach (already familiar with the basic concepts).  There also appeared to be adequate material on the web to help guide me through various Personalization methods.

>> Within the Form Personalizations (Requisition Summary) form

Function Name: PO_POXRQVRQ
Form Name: POXRQVRQ

Seq: 5
Description: Throw Message
Level: Function