Here's a trick I use that might help.
Go to a map that has a functioning version of what you're trying to make work. Lets say, in this case, load a map in UnrealEd with a beampoint that sends marines or whatever. select beampoint in the actors, and place a new beampoint right next to a beampoint that you know (or strongly suspect) controls marines in the same fashion you wish to control them.
Now, select both beampoints, and view their properties (the properties window should say "BeamPoint Properties (2 selected)"). Expand every [+] and look for blank areas. When you select two things that don't share a certain attribute, that attribute section will list neither attribute (leaving it blank), giving away that the two attributes are different. In this way, you can determine exactly what attributes need to be changed from the default attributes to the ones that make the actor function how you want it to. Of course, some attributes will be different for other reasons (such as movement > location and object > name), and others may just be blank. To find out the difference between the two, leave up the properties window, and then select only one of the beampoints, take note of how it's set, and then select the other, and take note of how it's set. Then of course, do your best to figure out if these differences are relevant or irrelevant to what you're trying to acheive.
This is the most useful trick I've found to use in UnrealEd. I've learned MANY things with it.
