Why do I get a syntax error when I try to print a nested hash that has keys containing colons?

I'm trying to print an element of a nested data structure:

$VAR1 = {
  'SOAP:Body' => {
     'ns1:MT_DF_AssetMaster_Response' => {
       'SUBNUMBER' => {},
       'ASSETCREATED' => {
                         'SUBNUMBER' => {},
                         'ASSET' => {},
                         'COMPANYCODE' => {}
                       },
       'RETURN' => {
                   'PARAMETER' => 'timedependentdata',
                   'MESSAGE_V2' => {},
                   'ID' => 'BAPI1022',
                   'MESSAGE_V1' => 'HW5790',
                   'ROW' => '0',
                   'TYPE' => 'E',
                   'FIELD' => 'plate_no',
                   'LOG_NO' => {},
                   'MESSAGE_V3' => {},
                   'SYSTEM' => 'xxx',
                   'MESSAGE' => 'Invalid date transferred for field xxx:',
                   'MESSAGE_V4' => {},
                   'NUMBER' => '041',
                   'LOG_MSG_NO' => '000000'
                 },
       'xmlns:ns1' => 'urn:ariba.com:xi:OnDemand:Asset',
       'ASSET' => {},
       'COMPANYCODE' => {}
     }
   },
  'xmlns:SOAP' => 'http://schemas.xmlsoap.org/soap/envelope/',
  'SOAP:Header' => {}
};

print "$data->{SOAP:Body}->{ns1:MT_DF_AssetMaster_Response}->{ASSETCREATED}=>{ASSET}\n";

But I get a syntax error:

syntax error at ./asset_creation.pl line 85, near "{SOAP:"

How can I fix this?