Can you provide more information? Are you saying that you want people to sign-in before they can fill-in and submit the form?
Also, do you want people to save data locally before they submit? For HTML forms (embedded or not) we do not support saving the form data but you can send an email receipt to the fillers after they sucessfully submit the data (look under the Options Tab). If you distribute the PDF form instead of the HTML form then the user can save the data (or work in progress) and submit.
People will already be signed into their website account when they fill out the form. It's not available to casual browsers. Other content that they access saves their input (e-learning feedback, like Captivate) so if this form did (rather than downloading the form separately), it would make the user experience seemless rather than fragmented.
You cannot display the PDF dirrectly in the browser (if this is what you are trying to achieve) and expect your fillers to fill the form directly fdrom the browser (including save). The PDF needs to be filled out within Adobe Acrobat, Adobe Reader or Acrobat Mobile. Browsers like Chrome and Safari who can display PDFs do not offer all the functionalities needed to submit the PDF to FormsCentral. The filler needs to download the PDF and open it Adobe Acrobat, Adobe Reader or Acrobat Mobile to fill it out.
You can distribute your form as an HTML form and embed it in your website (let me know if you need help with that). This way your filler won't need to download anything and they will be able to just fill out the form directly in the browser.
Does this answer your questions?
Sorry for the massively delayed response. I came to the same conclusion. No way to get FC to talk to my LMS?