I'm assuming you have access to the 2-bit setup, if not you can get it just by asking on the 2 bit forum thread.
If you click on the + beside the bit size, it will allow you to choose a detail bit:
I can't show pictures for this next part since this isn't the computer connected to the X-Carve, so you'll just have to go by my description and memory. Here's the procedure as I remember it:
-Your first cut will be the rough cut, so enter the feed/speed you want to use for the large bit.
-Click Carve, and zero your bit.
-On the bit size screen, it will let you select either the rough cut or the detail cut. Select the rough cut.
-Go through the rest of the pre-Carve screens, and do your rough carve.
It doesn't tell you to change bits, it just says that it's done carving. Don't move the spindle/router or the workpiece yet.
-Change the feed/speed to whatever is appropriate for your detail bit.
If your motors lock when you're not carving, you should be able to replace the bit without moving in the X or Y axes. If you can move it easily by hand or you're not sure, search the forums for "$1".
-Put your detail bit in your spindle/router. Be sure you physically turn off or unplug the router, safety police, blah blah blah.
-Zero the bit in the Z axis.
-Tell the machine that your bit is in the new home position, don't use the previous home position.
-On the bit size screen, select the detail cut.
-Continue through the pre-Carve screens and carve away.
In procedure form like that, it looks a lot more difficult than it really is. Just make sure you have a detail bit selected and make sure you choose the correct type of cut (rough/detail). As far as Easel is concerned, you have 2 potential cuts selected for the project and you have to choose which one you want to do. There is only 1 set of feed/speed settings though, so you have to change that as needed for each bit.