Cross references between files

[onegen]

Dear all,

I'm using lyx (1.3.0) to write and manage a set of files. The idea is 
to use the lyx-source files to make web pages and pdf-files automatically.

I have trouble with cross references between files. The "extended 
features" document explains how to do this: open both documents and 
choose a label from the target document.
The result is a cross-reference box that looks like a regular one.

When I create a DVI file,  I see ?? instead of a reference.
When I export to HTML, an internal reference is created, which of 
course leads nowhere.

When I include the target file, this works fine of course. But I want 
to keep the different files separate.

I tried adding the name of the target file in front of the label name, 
but this didn't help.

Using the XR package worked in tex-files, but not in Lyx.

Thank you for your help.

Onegen