AS400/Access 2007 Table relationships

I work with files on an AS400. I have no control over the file structure. As a simplified example, the AS400 file structure is:

Table Name: CUSTOMER

(k)ACCT#.....DECIMAL ........ (8.0)
   FName ....CHAR................. 30
   LName.....CHAR................. 30
   Date.........DATE................. 10

The Access 2007 file structure is:

Table Name: tblNOTICE

 (k)Index .............  AUTONUMBER...
(fk)NACCT# ...........DECIMAL............0
     NoticeDate ......DATE ................10

What I want to do is send out notices to delinquent customers. The demographic info (name, address, date of first order, etc) is stored on the AS400. I keep a separate Access database that I use to send out notices. I want to set up a form that prints a delinquent notice and records the date the notice was created. I want the [NACCT#] to be automatically populated with the [ACCT#] from the AS400 table to create a 0ne-to-many relationship with the AS400 file. The [NoticeDate] will be entered by the user.

The problem: When I try to create a One-To-Many Relationship between the AS400 and the Access table I do not have the option to select REFERENTIAL INTEGRITY. How can I get REFERENTIAL INTEGRITY between the two files automatically?