Help me here...

....how do I get the chase-camera thing to work in Legacy?

Try the console. Press C and press tab to cycle through all the commands beginning with C. There'll be a chasecam on/off (1/0), distance, and height setting.

I thought that by default pressing c toggled it ingame.

Yep.Or just type in chasecam 1.

Ah, legacy's nothing since v. 1.27...too buggy...nice, but just too goddamn buggy.

I used to use v1.28 all the time before I got fond of Millennium. Now I usually use ZDoom since I tried the last beta and never realized how damn fast it runs.