Build definitions for Visual Studio can use msbuild or devenv compilers. So if you can build your website with msbuild.exe compiler than you can use RTC build definition also to build the same website.
Normally you can do it when you have a website created as a Visual Studio Project. In that case above article you posted can be used. 

Now if you also want to use Jazz Ant Tasks as the article main scope is then
you can try this approach instead of article approach. ( There are quite a few ways to do what you want to do)

You create a MS Build XML  file in which you are going to call Ant to use your Jazz Ant tasks to do what ever you want using those  tasks.

example:

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="Build">
    <Exec Command="CALL ant -f $(fetchDestination)\build.xml -lib $(BuildToolKit) -DuserId=$(BUILD_USER_ID) -Dpassword=$(BUILD_PASS) -DrepositoryAddress=$(REPOSITORY_ADDRESS) -DbuildResultUUID=$(BUILD_UUID) target_Name"/>
  </Target>
</Project> 

Above the ANT target your are building is the <target Name> which is defined in the build.xml
Substitute <target Name> with the target that actually exists in your ANT build.xml which you want to execute.

Share this MS XML file in RTC.

Now in Build definition you can call msbuild.exe on how ever you want to build your website and then in the same Build definition second call you make to the above MS XML which will call Ant so you can use Jazz Ant Tasks.

If you can not build your website with msbuild.exe then probably you are better off using a command line Build definition and then execute what ever you want to build your website and then call ant to use jazz ant tasks.