HMRC Online Returns - Previous Years

[over_the_hill]

I have just completed a return for the 2012/2013 year and received a refund due to payments into a pension combined with higher rate etc.

Looking back to 2011/2012 and doing a quick calculation I think I might be due a refund there as well.
However, there does not appear to be anyway to submit a return for that year on-line.

Is this well hidden or is it actually not possible and do I need to get a paper form.

p.s. I am in paid employment and am PAYE so this is just for adjustments and not my total tax payment.

thanks