RQM with Graphic attribute for signatures

Hello,
per regulations I need to include the digital signature at the end of every single execution record, the only way that I can do it for now is adding the image as attachment, but for me it doesn't work really well because I can put other things as attachment as logs or wherever file so that is way I need specific fields for specific signatures required (I'm not talking about electronic signatures thro user and passwords).
Or other option that could work for me is to have the ability to add custom attributes type attachments(s).
Thank you!