change preserveAspectRatio="none" to preserveAspectRatio="xMidYMid meet"

I try to convert epubs with svg-tag in titlepage.xhtml containing the attribute preserveAspectRatio="none" to kepub, altering it to preserveAspectRatio="xMidYMid meet". So I put the following regex in the Search & Replace part of the conversion dialog:

<svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="none"([^>]+)>

to be replaced by

<svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid meet"\1>

When I look at the resulting kepub it still contains preserveAspectRatio="none" in the svg-tag. What am I doing wrong?