So official English TC Help states:
The same page in Russian Online Help by Konstantin Vlasov:TC Help: 'Working with archives (ZIP, ARJ, LZH, RAR, UC2, CAB, ACE, 7Z)' page wrote:Restriction: You cannot add files to any subdirectory of an archive, except with the internal ZIP packer and with UC2. However, you can add whole directories with all their files. You can choose whether you want to save the packed files including their paths, or simply the files alone. To add files to a subdirectory with the internal packer or with Uc2 you must separate the subdirectory with a forward slash / , not a backslash!
Example: zip:c:\test.zip/this\is\a\subdir
http://flint-inc.ru/tchelp/#packedfiles
writes that TC can add not only to subdirectory of internal ZIP and external UC2.
It says it's possible for internal ZIP-, TAR- and TGZ, and also external RAR, UC2.
It seems like info in English Help is not as full as in Russian Help.
Would be nice to see the comment on this from Russian Help co-author, Flint. If the info from Russian Help is verified to be correct, I think is worth to add its info to official English TC Help too.