Response Expression "KEY function" is always returning an empty string

Products

• CA Single Sign On Secure Proxy Server (SiteMinder)
• CA Single Sign On SOA Security Manager (SiteMinder)
• CA Single Sign-On

Issue/Introduction

- KEY function usage on the policy Sevrer 
- Followed the Docuemnt to configure KEY Function within an http header Variable Response 
https://docops.ca.com/ca-single-sign-on/12-52-sp1/en/configuring/policy-server-configuration/attributes-and-expressions-reference/operators#Operators-KEYFunction--LookUpKey

- Response keeps returning empty 

Environment

Release:
Component: SMPLC

Cause

This is a Known issue with KEY Function and impacting all CA SSO Releases 

Resolution

If you are Experiencing the same issue, please open a case with CA Support and request a DEV fix for the same.
The DEV fix will be generated for your CA SSO Release based on Defect DE375003.
After Fix is deployed, the function can be tested as follows:

* Expression configured in WAMUI is as 
"KEYExpTest=<$expr="KEY('C:\expr\schedule.dat','IAM','<start>')" $>", 

* The contents of the .dat file is as below: 

<start>=<20180712080000> 
[IAM] 
<start>=<20180712080000TEST> 
<end>=<20180712120000>. 

The point to note is, in the above example, '<start>' is the key. The key should match the expression configued in WAMUI and the .dat file. 
The output when a transaction is run will be 'KEYExpTest=<20180712080000TEST>' 
ie., the first <start>'s value after 'IAM'.