How can I make textpos respect beamer overlays?

Question

I'm using textpos to position text blocks in a beamer frame. However, the textblock environment does not seem to respect overlay commands. In the following example, I want "some more text" to be invisible on the first slide and visible on the second. However, when I compile the document, it is visible on both slides. How can I make it invisible on the first slide?

\documentclass{beamer}

\usepackage[overlay,absolute]{textpos}
\setlength{\TPHorizModule}{1cm}
\setlength{\TPVertModule}{1cm}

\begin{document}

\begin{frame}
Some text

  \visible<2->{
        \begin{textblock}{5}(6,6)
            Some more text
        \end{textblock}
          }
\end{frame}

\end{document}

Edit: Both of the answers that have been given so far are quite useful, and I am not sure which one to accept. On one hand, CyberSingularity's answer allows me to use multiple textblock environments with a single overlay command, while Paul Gaborit's answer would require a different overlay command for each textblock. On the other hand, Paul Gaborit's answer allows me to use the \visible command. I prefer \visible to \only, since, as cyberSingularity noted, \visible reserves the amount of space that it needs.

Answer 1

It works as expected if you use \only instead of \visible:

\documentclass{beamer}

\usepackage[overlay,absolute]{textpos}
\setlength{\TPHorizModule}{1cm}
\setlength{\TPVertModule}{1cm}

\begin{document}

\begin{frame}
Some text

  \only<2->{
        \begin{textblock}{5}(6,6)
            Some more text
        \end{textblock}
          }
\end{frame}

\end{document}

Answer 2

It works as expected if you call \visible into your textpos environment:

\documentclass{beamer}

\usepackage[overlay,absolute]{textpos}
\setlength{\TPHorizModule}{1cm}
\setlength{\TPVertModule}{1cm}

\begin{document}

\begin{frame}
  Some text

  \begin{textblock}{5}(6,6)
    \visible<2->{
      Some more text
    }
  \end{textblock}
\end{frame}

\end{document}