How to specify multiple buildtypes in devenv tasks, CruiseControl.net

Question

I want to do Clean and Build in devenv. I just noticed that buildtype flag can have only one item (Clean;Build not allowed). Do you have any idea how to specify multiple BuildTypes?

<tasks>
  <devenv>
    <solutionfile>C:\Source\Developer.sln</solutionfile>
    <configuration>Release</configuration>
    <buildtype>Build</buildtype> // How to do Clean and build here???
    <executable>C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\devenv.com</executable>
    <buildTimeoutSeconds>900</buildTimeoutSeconds>
  </devenv>
</tasks>