Took me a while, but I figured it out.
1. Install Homeworld: Emergence / Cataclysm
2. Locate cataclysm.big , extract everything somewhere temporary with the "WinBigW" program. In a pinch I will upload it somewhere.
3. Now you can edit almost everything in this game
4. In the extracted files, find "warp.script" , this lets you start single player in a certain mission
5. Edit the file with Wordpad/Notepad into this:
WarpEnabled 1
LevelToWarpTo 1
And change the tech in mission one from this:
Tech TECH_DRIVE_FIGHTER
into this list:
Tech TECH_DRIVE_FIGHTER
Tech TECH_LINK
Tech TECH_SALVAGE
Tech TECH_REPAIR
Tech TECH_MIMIC
Tech TECH_AFTERBURNER
Tech TECH_MICRO_SHIP
Tech TECH_DRIVE_FRIGATE
Tech TECH_FORCE_FIELD1
Tech TECH_CRYSTAL_HARVEST
Tech TECH_ARMOUR2
Tech TECH_EMP
Tech TECH_ENERGY
Tech TECH_ION
Tech TECH_FORCE_FIELD2
Tech TECH_ADVANCED_SENSORS
Tech TECH_DRIVE_DESTROYER
Tech TECH_ARMOUR3
Tech TECH_REPAIRBOTS
Tech TECH_FORCE_FIELD3
Tech TECH_ADRIVE_FIGHTER
Tech TECH_ADRIVE_FRIGATE
Tech TECH_ADRIVE_DESTROYER
Tech TECH_MISSILE
Tech TECH_PHASED_TELEMETRY
6. You can also edit the .shp files in the "\race_sect\" submap.
7. Don't overdo it or you'll get some weird results. E.g. the beast infection beam always does 20% damage.
8. When you're done, just copy the files to wherever you installed Homeworld Emergency. The Somtaaw .shp files go into the "\race_sect\" submap.