I've been experimenting along similar lines as you are, for keltos01 and the Climb Mount Niitaka, and I'm encountering similar issues. I'm not sure if it's "environmental", or something with the settings in the ships themselves. I haven't gotten that deeply into it yet. I want to try to find something "concrete", you know? - SIM files?? It seems to be ships' physics, but I don't know. Something that works reasonably well in FotRSU, but not outside of it... But the game really is full of balancing acts, and not having the documentation that the devs had, we don't have the ins and outs, so, "experimentation" is the word of the year, or however long it takes...
As for faking the Ultra messaging, I was going to try several ways concurrently in a single MIS file with several RGG in it, in the campaign folder, emptying all the other Campaign files out of there, other than the necessities. Then see if the "ReportPosMin=" and "ReportPosProbability=" working with the "HighPrioContact=" (or not), generates a strong enough report (it'd just be in the little text box where crew dialog shows, or whether I'd use a Trigger / Event in the MIS file to generate an actual prompt and "Radio Message" that would pop-up on the screen, or maybe a "normal" message from the "messages.txt" file that you get a prompt about, but doesn't open, or maybe use a combination of some or all of them... Does it appear then that the "messages.txt" stuff does hit when the date / time are encountered? Have you tried a "Save / Load" of the mission and see what that does to the message that way?...
Ratz, sorry mods, we're doing this in the Reports thread... I'll start another thread tomorrow Bubblehead1980, and we'll discuss this fun kind of stuff in it...
