Our support for MS Dynamics NAV Web Services includes any Page object that you expose as a WebService. This means that virtually any data in NAV can be created and updated in this way.
Furthermore the access to NAV is still very secure as we use our RapidiConnector to access the WebServices - this means that you dont have to open up your firewall to allow incomming connections to your NAV WebService Server.
We still recommend to use the C/Front based RapidiConnector to read data from MS Dynamics NAV - its just so much faster this way. Also features like SourceControl is not available in the WebServices, making it hard to transfer only the changes.
Here are some more installation/setup details:
http://wiki.rapidionline.com/wagn/MS_Dynamics_NAV_Web_Services