How to add a new object to an existing Group.

Just select an object from the group (not the group itself; you must select one of its objects) and then make your new object. The new object will be added to the existing group.

How to import Illustrator artwork and be able to change its color.

In Illustrator, make sure that each object has either a fill or a stroke (not both). Now make sure that each object or group is on a separate layer (if you have Illustrator 9, you can just choose Release to Layers from the flyout menu in the Layers palette). Color each object black (either its fill or stroke, depending on which it has), and save the Illustrator file as version 8.0 (or older). Now import it into LiveMotion, and choose Object -> Convert Layers Into -> Group of Objects. You can now select any individual object (or group of objects, if you had more than one object on a layer in Illustrator) and color them whatever way you want.

How to import artwork at actual size (without scaling).

As you've noticed, LiveMotion will scale any placed files to fit the composition (if your composition isn't large enough to accommodate them at their original size). However, it's easy to make them actual size: once you've placed the file, just choose Object -> Transform -> Clear Transforms.

How to resize objects the normal way.

LiveMotion resizes objects from their anchor point, which by default is at the center of the object. This method of resizing is different from what you're probably used to; you're no doubt used to resizing from the top-left. You could move the anchor point, but that's imprecise and slow. To resize from the top-left, simply hold down the option key (Mac) or the alt key (Windows), and drag the lower right handle of the object.

How to do shape-tweening (sort of).

Two methods:

1. Place your original shape at the beginning of the timeline, then set Replace keyframes for each tweening point. At each keyframe, use the Edit Original command to go to Illustrator (or whatever) and alter the shape.
2. In Illustrator, draw the beginning shape and the end shape, and do a blend. Put each step of the blend onto a separate layer, then import the file into LiveMotion, choosing Object -> Convert Layers Into -> Sequence.

How to proportionately scale non-proportional objects.

You've drawn a rectangle or such, and you've sized it such that it's not proportional (its length is greater than its height, or vice versa). You now want to scale it up, maintaining its current proportions. But, if you shift-drag (the usual way to proportionately scale objects), it snaps to being completely proportional (length=height). So, how do you proportionately scale a non-proportional object? Simple: just group the object, then scale it, then ungroup it. It's perfectly okay to group a single object, and it lets you proportionately scale it from its current proportions.