So, we had a discussion about this with our agent ( who we regret now to even hire one and waste money because they are so incompetent). They are of the opinion that email sent to case officer is good enough. We wanted them to email and upload the file to be on the safer side but they just denied our request and emailed the case officer. I do not know what is right , what is wrong. reading the few threads here, i created an immi account and uploaded the files myself and clicked the button. The button doesnt really matter. What is important is to click the button after the requested documents have been updated.