If you're just looking to add a weapon, I wouldn't go into the editor to do it. The BF2 Editor reads the 'Editor' folder of a map. These are not included in the normal game. This is why almost nothing shows up when you load a map in the editor. (Also, where are you finding 'seelow-coop?' I don't think Seelow has bots added to it?)
What I would do is navigate to the gameplay objects folder for the 64 layer;
C:\Program Files (x86)\EA GAMES\Battlefield 2\mods\fh2\levels\seelow\server.zip\GameModes\gpm_cq\64
This is what the game reads to load up all of the spawners in the game (soldier spawns, vehicle spawns, pickup kits spawns etc...)
open the "GamePlayObjects.con" file in notepad and Ctrl+F for 'pickup'. This will find the pickup kits that are placed on the 64 layer of Seelow Heights.
You'll want to find something like 'GW_PickUpPanzerfaust60m_VS' or 'GW_PickUpPanzerfaust100m_VS.'
Pretty sure these stand for GW=German West, Pickup=Pickup Kit, Panzerfaust60or100m= Panzerfaust, VS= Volkssturm. The 60m has the VG-45 and the 100m has the VK-98.
From there I would go to another map (whatever map you want to put these weapons on) and paste one of the kits into one of that map's pickup kit.
For example; if I know the location of the anti-tank kit at Mont on Bastogne, I would find that in the GamePlayObjects.con for that level.
rem [ObjectSpawnerTemplate: CP_64_coop_mont_DE_US_Antitank]
ObjectTemplate.create ObjectSpawner CP_64_coop_mont_DE_US_Antitank
ObjectTemplate.activeSafe ObjectSpawner CP_64_coop_mont_DE_US_Antitank
ObjectTemplate.modifiedByUser "WSU"
ObjectTemplate.isNotSaveable 1
ObjectTemplate.hasMobilePhysics 0
ObjectTemplate.setObjectTemplate 1 GW_PickUpPanzerfaust100m
ObjectTemplate.setObjectTemplate 2 UW_PickUpBazookaM9
ObjectTemplate.minSpawnDelay 120
ObjectTemplate.maxSpawnDelay 240
I would then replace 'GW_PickUpPanzerfaust100m' with 'GW_PickUpPanzerfaust100m_VS' (or whatever you want).
Then save the new .con file.
HOWEVER, a simple copy paste won't work. I
think you have to re-pack the map. (this does some voodoo that puts all the files in a place where the game can read them
)
To pack a map you have to use the 'pack-map.py' that is located in the FH2 folder. this is a Python script that you need to have Python installed to run. When you run it, it will open the command prompt and ask you to type in a map name. Just type the name of the map you're packing and it should run a script that packs it for you.
*disclaimer* even this might not work. I haven't tried it because I don't have Python on this computer and map packing is pure voodoo to me. Maybe a more experienced mapper or coder can help you out.
Hope you can get a gun added to the map you want. That's the first step in getting addicted to modding. Maybe you'll get interested enough to make a map or weapons or something one day
Also, back up your files, 'cause if you fuck them up enough you'll have to use the 'Repair' option in the launcher to get everything back to where you can play online.