Move accounting data from Xero to Clearbooks

I run a small firm of accountants. I'd like to move my practice bookkeeping from Xero to Clearbooks. So contacts, opening balances and most importantly customer balance breakdowns. I have around 600 clients and half of these will have activity that needs to be replicated. So what I want is Clearbooks to replicate Xero. Experience of both systems would be required. My year end and last VAT quarter ended at 31 August 2014. So that would be a good starting point. Ideally also need transactions bringing up to date too.