Hello May be this suggestion has already be made: there exists now an openoffice to latex export and import filter, including mathematical formula.
1. Oolatex is a script shipped with tex4ht, which converts latex to sxw files. 2. Writer2latex is java export filter which converts sxw files to latex. I think the first converter could be easily accessed from lyx. The second one requires java, and can be also executed from the command line. The latex file produced will need a special writer.sty. Uwe Brauer