Alright, I assume you already know how to export using Blender 2.49
So I'll skip to the sequence tab

When you export, it doesn't matter the name of the animation as long as you remember what you named your shoot and equip animation.
I named mine Equip and Fire for simplicity's sake.
Make sure that when you have animated you know which frames are for which animations, if you fire animation starts on frame 1 and ends on 5, make sure to set the starting to 1 and the ending to 5, otherwise it will conflict with other animations, and you can't have animations overlapping.
MAKE SURE YOU DONT SELECT DSQ, weapon animations don't use dsq animations and are stored in the .dts file
After that set the export location and export like you normaly would.
Now you are onto the scripting part
For this I took part of the default Weapon_Gun's image script.
// Initial start up state
stateName[0] = "Activate";
stateTimeoutValue[0] = 0.15;
stateTransitionOnTimeout[0] = "Ready";
stateSound[0] = weaponSwitchSound;
stateName[1] = "Ready";
stateTransitionOnTriggerDown[1] = "Fire";
stateAllowImageChange[1] = true;
stateSequence[1] = "Ready";
stateName[2] = "Fire";
stateTransitionOnTimeout[2] = "Smoke";
stateTimeoutValue[2] = 0.14;
stateFire[2] = true;
stateAllowImageChange[2] = false;
stateSequence[2] = "Fire";
stateScript[2] = "onFire";
stateWaitForTimeout[2] = true;
stateEmitter[2] = gunFlashEmitter;
stateEmitterTime[2] = 0.05;
stateEmitterNode[2] = "muzzleNode";
stateSound[2] = gunShot1Sound;
stateEjectShell[2] = true;
stateName[3] = "Smoke";
stateEmitter[3] = gunSmokeEmitter;
stateEmitterTime[3] = 0.05;
stateEmitterNode[3] = "muzzleNode";
stateTimeoutValue[3] = 0.01;
stateTransitionOnTimeout[3] = "Reload";
stateName[4] = "Reload";
stateSequence[4] = "Reload";
stateTransitionOnTriggerUp[4] = "Ready";
stateSequence[4] = "Ready";
Now, the parts you are looking for are the "
stateSequence[num] = "animation_name_here";"
States start at 0, not 1.
In the gun's script, state 2 controls firing you should see "
stateSequence[2] = "Fire";", now when we exported we named the shooting animation Fire(or atleast I did) So that sequence is correct, if you named it something different you need to change Fire to what you named you sequence.
I'm not entirely sure, but I think state 0 is where the equip animation would be stored. So do to this I added "
stateSequence[0] = "Equip";" to the code like this:
stateName[0] = "Activate";
stateTimeoutValue[0] = 0.15;
stateTransitionOnTimeout[0] = "Ready";
stateSound[0] = weaponSwitchSound;
stateSequence[0] = "Equip";
Again, make sure you set the correct sequence name where I put Equip.
That's all there is too it, ask questions if you need to