I'm having problems to open word and excel files throught NetStorage.

When i open a document in MS Office Word via NetStorage, this document is
opened as Read-Only.

It problems occurs when i access the NetStorage by a public IP address. I
mean if a open a document like
it works fine, but when i open a document like
ueba1.doc it doesn;t work, the document is opened as read-only.

I'm using an ICS to map the public address to internal address.

Any idea ?