Portal Server Side SharePoint Integration

Very basic question that I am struggling to find the answer to. I have created my CRM Portal and enabled the new SharePoint Integration features on the Portal. I am going to use Portal to give externals customers access to the SharePoint library associated with their CRM Entity. Question is will this work if the SharePoint setting on Office 365 is not set to allow sharing with externals?

I am assuming it won't but can't see any mention of it in any documentation.