Can I download the summary information model from S-INFO to IFC?

Yes, you can!  If you really need it, you can download the summary model of the entire object or any part of it, for this: 

1. Select the required model elements. 
2. Select “Export to IFC” from the context menu. 
3. If the model is very large, then stock up on popcorn, but if it’s not very large, then you won’t even have time to get out of your chair. 

And by the way, if you forgot, files linked in S-INFO can turn into links, see – How to attach a document to an IFC file?