Authorization for saving Default Layout Settings

Question

Hello,
In transaction /AFS/MD04, we would like to restrict users from changing the default screen layout.  When they try to save a screen layout, we would like the checkbox to default to "User-specific" and not allow them to change the default. 
     Also, we would like to restrict those who can change the default with a parameter id. 
To recreate:  Enter a material and plant number and press enter.  On screen 2000, subscreen 800 is the screen to which I'm referring.  It is here that we would like to control the settings. 
I have done this in custom reports using the following code:
*Check authorization to change default layout
  GET PARAMETER ID 'ZSD_VARIANT_RETURNS' FIELD lv_pid.
  IF lv_pid = 'X'.
    lo_layout->set_default( abap_true ).
  ENDIF.
I have seen some posts refer to transaction SHD0.  Can this be handled with that transaction code?
Update on 3/2/2010:
I have seen some other posts regarding this issue and also seen OSS notes 409190 & 601803. 
Our security team says that changing auth object S_ALV_LAYO would prevent users from changing the layout at all.  Is this correct?  We want to restrict who can set the Default Layout and give everyone else the ability to set the User Specific settings. 
I have seen other posts refer to the I_SAVE parameter, the OSS notes also mention it, but it isn't clear to me how to use that.
We would like to do this in a SAP transaction - /AFS/MD04 - is this possible?
3/3/2010:
It appears taking away authority to object S_ALV_LAYO was the answer after all. 
Thanks,
Chris Mowl
Edited by: Chris  Mowl on Mar 2, 2010 10:52 PM
Edited by: Chris  Mowl on Mar 3, 2010 11:24 AM

Answer 1

When object S_ALV_LAYO was taken out of my security profile, I was only able to save User-specific layouts and not Default layouts.  This was our objective.