Caption labelling problems

[Paul Medwell]

I am using a different caption under a table than in the List of Tables by inserting an ERT:
\caption[short caption]{long caption}

While the caption works fine, I am having trouble with the label. I create a label as I normally would ("Insert->Label") and then try to reference it in the document text with "Insert->Cross-reference". In the LyX display it comes up fine, but when I view the document (in dvi or pdf) it doesn't reference it, only displaying ??

How can I fix this?

Cheers,
Paul