Is it even possible with Wrye Bash to have a sub-package with only a file, that is not an esp/esm, for example an ini file? I have the following complex structure:

00 Core -> an esp and a INI folder with the default ini inside
01 My Setting -> only the INI folder with my customized ini inside
99 Docs -> just the readme

I want to have the possibility to switch between the default ini and my customized ini by checking/unchecking the subpackage box.

Problem: Wrye Bash does skip the 01 sub-package and I don`t know why.

Right-click on the package and select "has extra directories."

Klaus; you should probably posts such questions in the http://www.gamesas.com/index.php?/topic/1156281-relz-wrye-bash-thead-58/page__st__20

However; version 290 of Wrye Bash recognises the "Ini" folder name, older versions did not, and thus required "has extra directories" to be checked (which recognise more, but not all different folder names.)
And to your initial question; Yes, it is in fact common for sub-packages to have no esp/esm files. alternate Textures files for example. Some mods even have multiple sub-packages with NONE of them having any esp/esm files at all.

Ok, I`ll post in the WB thread from now on.

Unfortunately my problem is still there. I have WB 290 and I checked "has extra directories" (its in german in my version, I don`t know why), but the sub-package still does not show up in the sub-packages window. It is shown in the "skipped" window thought.