Your HintergrundFarbe 12632256 translates to hexadecimal as C0C0C0, which looks like a plausible RGB colour code, so I suspect you just want to do a decimal-to-hex translation. You can do that either by calling an extension function, or by writing it yourself as a recursive function (or template, if you're in XSLT 1.0). Or in fact as it's always six hex digits you could just compute each digit separately: the hex value of the 4th hex digit for example is
substring("0123456789ABCDEF", 1 + (($in div 256) mod 16), 1)
Michael Kay
http://www.saxonica.com/
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference