Please help me with WWNum1, etc. I am talking about list styles, I am using my own list styles (F11) and when I delete these WWNum1, etc, they appear again after reloading and my changes with my own list styles are not saving… This happens, when I convert .odt to .docx…
Could you please clearly state your question? It seems your “troubles” are limited to list styles, not the conversion in itself?
The conversion of list styles (e.g., the provided List N, Numbering N, or other custom definitions) to WWNumN labelled definitions is basically an artifact of the translation to OOXML (i.e., in the WW8 filter). This behaviour is the same under all versions from at least v3.5.7.2 to v4.3.0.2.
The question about page styles being renamed as convertedN is related.
How to get rid of these useless formats?
See this other question: How to get rid of WW8Num8 list style for a nicer presentation than this small comment.
@Aliasduelzone, I have re-opened the other question and provided a detailed answer. It is necessary to avoid non-native formats if these styles are to be avoided. The only solution is to re-style the document.
Here is issue about this problem with more detailed info and examples: https://bugs.freedesktop.org/show_bug.cgi?id=81331
Thanks for reporting the bug and providing examples. I have confirmed the issue and clarified it somewhat. Let’s see what the developers have to say about the WWNumN list styles (when saving to DOC) appearing to be based on the format of the identifier, rather than the item text (and why this definition is not as exact as expected). Note that this is a slightly separate issue to that initially asked in this question.
I can confirm your problem in LibO 4.2.4.2 running on XP/SP3.
I recommend to file a bug report under: https://www.libreoffice.org/get-help/bug/
May I ask you to publish thereafter the bug number here to allow other users to add comments?
It could also be that MSO docx format requires this. I recommend also to read @oweng 's article: http://en.libreofficeforum.org/node/7505
In general I always work only in LibO’s native formats and change to an MSO format only when a pdf-file cannot be used. The change to the MSO format I make only at the very end. Currently I prefer the older doc format. doc-format does not create the WWNum1 list style.
It’s not a bug, OOXML doesn’t support named numberings, while ODF and LO does. So on saving, the names are discarded and when you load the file back, the WWNumN names are generated, as oweng says. So please don’t report it as a bug, it would be just closed as not-a-bug anyway. Thanks! 
@vmiklos & @oweng - Thanks for this information. Then MSO’s formats are worse then I thought. I am glad I am using LibO!
I’m using LO v.4.2.5.2 and system is W7 32.
yeah, thanks for the information anyway.