There is an option you can set in the Assemble Options that will automatically capture them during placement. Maybe you had that set in ST7?
It's not in Solid Edge Options, it's in the Assemble command. Click on the 'Options' button on the Assemble Command Bar:
That button will bring up the dialog I posted above. Some of these options are also available in Solid Edge Options, but not all of them.
Hope this helps,