Hi Niki.
http://www.indian-bank.com/downloads.htm#loanappln
please go through the url mentioned above, u will get the online educational loan application form.
In the last page of the application form they have mentioend all the documents that has to be submitted.
coming back to your question, the signature of ur uncle is enough, he doesn't have to be physically present.
i am myself applying for educational loan and had a talk to the bank managers regarding these issues.