Comperio
27th April 2007 00:44 UTC

GetDlgItem $1 $HWNDPARENT 1
EnableWindow $1 0

Use this in the page's show function. If course, you'd have to re-enable it at some point or your install won't get far! ;)

PS:
Use !define MUI_WELCOMEFINISHPAGE_CUSTOMFUNCTION_INIT YourFunction to setup a custom welcome page init function. Or you could use MUI_PAGE_CUSTOMFUNCTION_SHOW or MUI_PAGE_CUSTOMFUNCTION_LEAVE. These are all in the MUI docs.