When you create a ticket in Customer Portal, it allows you to upload a file (not sure what is the maximum size), but if you want to upload files within the ticket after creation, there's a limitation of 30 MB only.
Can it be improved please?
Also, you can select muliple files to upload, but when you choose and try to upload, only the first file selected gets uploaded. In other words, Customer Portal does not allow you to select and upload multiple files at the same time.