OK, I'll post the "problems" I've come across following your steps:
In SLADE 3, open your mod and the IWAD that you are modding for. (So, if you're making a Doom II level, open doom2.wad.) Copy the PNAMES, TEXTURE1, and (if it exists) TEXTURE2 lumps from the IWAD to your mod.
Select the tab with your mod, and click on the "Texture editor" button in the toolbar (it's a blue T next to a green M). This will create a new tab with the texture editor for your mod, subdivided into smaller tabs for TEXTURE1, TEXTURE2 (if it exists) and PNAMES. You can ignore PNAMES for the moment.
Open the CC4 texture pack. Click on the texture editor again. You now have two texture editor tabs, one for your mod and one for CC4.
Browse through CC4's texture. When you see one you want to use, copy it (select it and right-click copy, or Ctrl-C). Then you can paste it in the texture editor for your mod (go to the end, then right-click paste, or Ctrl-V).
Once you've finished adding all the textures you like, go to the PNAMES tab on your mod's texture editor. Scroll towards the end, and see all the patches that come from CC4 instead of Doom2.wad.
In the archive (not texture editor) tab for CC4, look for these patches. Select them, and copy them (right-click copy, or Ctrl-C). In the archive (not texture editor) tab for your mod, paste them. To make things more cleanly, create a P_START and a P_END lumps (using the "New Entry" button on the toolbar), and paste all your patches between them.
If you want to copy flats too, it's a bit simpler. Create an F_START and an F_END lumps. Copy the flats you like from the archive tab of CC4 to the archive tab of your mod, between F_START and F_END.
Make sure that none of the lumps you have added (created or copied) are inserted in between map lumps. A map start with a header (like MAP01 or E1M1) and ends with the BLOCKMAP lump in Doom format, the BEHAVIOR or SCRIPTS lump in Hexen format, and the ENDMAP lump in UDMF.
Also make sure none of them are placed in the wrong namespace, for example between S_START and S_END markers.
Step 1 = I've done this, but when I search for the PNAMES and TEXTURE1 lumps in my mod, it's already there???? Only the size of these two lumps in my mod is a bit bigger...
Step 2 = Done this as well, except it opens not one tab for TEXTURE1, but several (5) tabs and 1 for TEXTURE2
Step 3 = This step seems to be alright according to your explanation.
Step 4 = The problem here is what do you mean by "go to the end"? And which one of the 5 do I need to copy-paste in ??
Step 5 = I've tested this step with the MIDRAIL2 texture, just to try it out and this seems to be fine because I found the texture on the bottom, but there's a whole lot of other textures as well??
Step 6 = I don't get the second half of this step...
Now, when I go to Doom Builder again and look for the MIDRAIL2 texture it's not there. However, when I go to Flats it's there, except the actual texture is not visible and instead I see a red cross.
[Edit] In 3d mode the texture is all black, but then when I playtest the map I am able to see the new texture. Weird
Thanks for the offer, but it's not like it's an issue. It's just that I want a little extra for my mods. Besides, I don't want to bother you (or anyone else) with my "problems" this way.
If making your map dependent on a texture wad looks like becoming an issue, you should consider Searcher's other suggestion...
I'm available if you decide to go that way.
Last edited by djvero on 11-03-12 at 16:51