Importing Custom Weapon to the Game?

[alter5]

So i followed the tutorial on this site http://social.bioware.com/forum/1/topic/72/index/320619 everything went right till Step 5

because the only files i have are "mmh, msh, phy and mao." but in the tutorial they ask for some so called gda, dda and 2da. files

and theres my question where i can find or how can i create those and are they really necessary?