If you have problems when using XSLTsearch extension for umbraco on version 4.6 installation the easiest way to resolve it is to simply complile the .cs file to a .dll using Visual Studio and then declare it as an xslt extension using the line below:
<ext assembly="XSLTsearch" type="PS.XSLTsearch" alias="PS.XSLTsearch" />
To make this even easier for you here is the .dll you need.
