In the control panel, how to set the Remove and change button

[gale_wang]

I have a InstallScript MSi project. Now,
Add/Remove program shows two seperate buttons :
CHANGE and REMOVE
If I click on any of them it takes me to the maintenance screen.
Justly, i would click on CHANGE, it takes me to the maintenance screen. And when i click on remove, I want it to uninstall the program rightaway.
Also, I tried ADDREMOVE_COMBINEDBUTTON = TRUE; it did not work either.
code in the OnMaintUIBefore():
if(MAINTENANCE) then
nType = MODIFY;
nReturn = SdWelcomeMaint("","",nType);

switch(nReturn)
case MODIFY: nType = MODIFY;
case REPAIR: nType =REPAIR;
case REMOVEALL:nType =REMOVEALL;
endswitch;
else
nResult = MessageBox( SdLoadStrin(IFX_MAINTUI_MSG ), MB_YESNO );
if (nResult != IDYES ) then
abort;
endif;
nType = REMOVEALL;
endif;

:mad: I want to know what condition i shoud set at "if(MAINTENANCE) then
".
Anyone has any ideas? Please help me ,thanks a lot!:)

[gale_wang]

I have soluted this issue.
First, change Install Information=>General Information=>General=>Enable Maintenance to 'No'.
Second, setting 'REMOVEONLY' condition to divide the Change and Remove button.
Thus, i would click on CHANGE, it takes me to the maintenance screen. And when i click on remove, it uninstalls the program rightaway. Perfect!