Hiya,
This is something we can help with - talkinpeace - we have seen people with the problems you describe and it can be fixed. There are a few different reasons including incorrect security settings, layout designs needing changing - and others.
no12rugby - as talkinpeace says you need to get the setting correct in your invoice design - we would be happy to help if you want to get in touch. The fact no address appears could either be that you don;t have an email address in the correct field in the customer account record - or the email setting are not correct in the layout you are using - which is fixed by going to into report designer and changing the settings for the layout.
This is something I am being asked about more and more at the moment - including helping the designs look nice on plain paper and adding in logos and click throughs to the pdf designs.