They can't, or at least I don't think they can. The actual point values for various encounters by CR are not in the SRD (or at least, they weren't when I last looked), so it's something they can't refer to.
Fortunately, there are a few Traveller players that dabble in D20 Systems, to help with some of this.
As for assigned CPs, or whatever you desire to call them, I personally think that, as Traveller is not a conquest-oriented game, you are doing a disservice to the genre and the system if you decide to go that route. IMO, YMMV, of course.
As it stands, Challenge Ratings (CRs) are based on the amount of challenge that the encounter represents in combat. Specifically, this assumes that a typical party of four adventurers of X character level can take out the encounter using only 25% of their resources. X then becomes the CR of the creature.
So, in order for you to assess the CRs of these encounters, you will first need to design a typical party of four adventurers. In D&D, that's a fighter, a rogue, a cleric and a wizard. You could use the same (but it doesn't seem right), or you could decide what the typical adventurer party in Traveller looks like (perhaps a Marine, a Navy character, a Merchant and a Scout). Then pit them against the encounter, using characters of various levels, until you hit the magic number.
Or you can take the less involved, more story-based route, and assign each encounter with a CR equal to that of the party's average character level, and modify for difficulty, as mentioned above.
I would recommend the second approach, myself, if I were to go that route. Frankly, though, I don't have a problem with the XP awards given in T20, and use them as is.
Hope this helps,
Flynn