What are my enforcement options for obtaining outstanding child maintenance?

For the last 3 years I have been dealing with the CSA to obtain payments for my 2 children. They have contacted my estranged husband and suffered gross non-compliance and they continue to allow him to ignore his responsibilities refusing to reply to letters and changing employment to slow down their processes - detachment of earnings? Last received payment in November 2010 and informed he is in arrears of over �5,000. I wish to place a charge on his property is this possible if not what can I do?????????????????