I solved my problem using c# SDK instead of OLE, so this is not exactly answer to question about OLE.
I recommend using SDK because you can benefit the predefined object model of official API while in com interop there is no such guide.
You must have Openoffice SDK installed on your system, then in your c# project add reference to all dlls in this directory:
...\OpenOffice 4\sdk\cli\cli_basetypes.dll
These pages have practical samples of using APIs of c#:
http://suite101.com/a/creating-an-openoffice-calc-document-with-c-a124112 (404) http://www.oooforum.org/forum/viewtopic.phtml?t=107055