Using VB6 several years,you may need add the windows object control,maybe usb interface control object to you project,so you can control or program it in VB6.
It depends on the device. There must be a user mode driver (dll) available for that specific USB device/class for VB to be able to talk to that USB device. There are general mode USB device driver, but you still need to know the specific device setup before hand.
Trying to use a USB device in VB is like sticking a needle in your eye! Unless you can get a hold of some DLL or OCX file to use to communicate to the USB device then that would be the way to go...... Unless it is a USB drive then you could use API to communicate with it, or if it is a USB camera then use WDM interface in Windows.....
Or if it is one of those FT USB IC'c, it should see it as a commport, then it is easy to communicate using the comm control.