Design Journal / Custom Propertie's

We will be starting to use the Design Journal feature for our custom projects and I have been doing a little research, however the information is very brief.

The questions I have are;

1.  Can I add SW Custom properties, The information I could find is to open the Journal and go insert field, however there was no custom SW properties, also the file opened as read only, so I couldn't save it

2. Is the Journal file a template or just a imbedded word document in the part or assembly

Any help is much appreciated,

Thanks

SolidworksGeneral