Hi and welcome to the forum. Do you mean retain savings you've accumulated prior to entering an IVA? If so I do believe these would be an asset and as such payable to your IVA. However, if you mean to accumulate some savings when in an IVA then it's possible with your share of any overtime or savings on your budget that is fine.
IVA final payment left the bank on the 26th January 2013...looking forward to a debt free future.
In addition to Lesley's good advice I would say that, if you are talking about savings already held before the IVA, you might be allowed to hang on to a modest sum for emergencies ( couple of hundred, maybe). This will depend upon your IP.
Most of us, after paying our bills etc before our IVA's didn't have any savings to hold on to, but some manage to save up a couple of months money that used to go to the loans while the IVA was being set up.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014