Good start. Unfortunetly if you want to modify the standard attack4 your best bet will be to start over.
First get the _humanoid.gla file out of assests.
Then go into your Dragon folder and remove or rename the '_JAhumanoid.gla' file.
Drop the _humanoid.gla file into Dragon and rename to _JAhumanoid.gla.
Copy the animation.cfg into Dragon fro easy use.
Run Dragon and find the Both_attack4 animation: BOTH_ATTACK4 1589 6 -1 20
Use the 'impframe' command like this: impframe 1589 6
That will import the attack4 animation into Dragon. If you're going to try modifying a gun fire there is an easier method.
1. make you gun stance, aiming that is.
2. save it then quit Dragon.
3. Open you gun stance and copy everything starting with 'frame 0'.
4. Paste it 2 times and rename the second and third 'frame 0' to 'frame 1' and 'frame 2'.
5. Open Dragon and load the stance. It should now be 3 frames.
6. Go to the middle frame and animate it to how you want the recoil to look.
7. Now go to the first frame and use 'fblend 4'. Then go to the recoil frame and also 'fblend4'.
That will give you a new smooth gun fire animation.