# Soul color transparency

I want to highlight some text using package soul. However, I fail setting the color transparency, which is normally possible by writing !trans_value after the color. As soon as I add this transparency value to the color:

\begingroup
\sethlcolor{red!30}%
\hl{some text here}%
\endgroup

It only colors the white spaces between the words. How can I fix this?

A workaround:

\documentclass{article}
\usepackage{xcolor}
\usepackage{soul}

\colorlet{soulred}{red!30}

\begin{document}

\begingroup
\sethlcolor{soulred}%
\hl{some text here}%
\endgroup

\end{document}

BTW, the part after ! in xcolor's color expressions has nothing to do with transparency. It means rather mixing with another color: 30 % red + 70 % white.

\documentclass{article}
\usepackage{xcolor,soul}
\begin{document}
\colorlet{usercolorname}{red!30}
\sethlcolor{usercolorname}
\hl{some text here}
\end{document}