SvcUtil error generating proxy from asmx assembly

Hi  I am trying to use SvcUtil  with asmx webservice to generate proxy class I get error: cannot generate XmlSerilaizer types for assembly .....No service contract types were found.

I tried to add service contract but it does not exist for asmx.

my command :  SvcUtil.exe    directory/bin/WebService1.dll   /out: directory/myproxy.cs

I noticed the command works fine when supplying end point  of web service in IIS: SvcUtil.exehttp://localhost....