How come this replies an error when process?
<xsl:variable name="entities" as="xs:string*" select="('&aeiubareiubar;','&aneiubareiubar;','&ar eiubareiubar;')"/>
As you can see, the variable is an array that needs to have values with entities but still the processor parse these strings and reply an error that it should be declared. Can I used these strings as plainly strings and not be interpreted by the processor as entities?
Thanks.

A stylesheet is an XML document and must be well-formed XML. That means that an ampersand must be part of a valid entity reference. If you want to use an ampersand in any other context, it must be written as &amp;

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

I see... So the result of it would be &aeiubareiubar; for this example. But it does not. I used a character map for $amp;amp but still no luck. Thanks.

No, the only possible result for this example is an error,because the stylesheet is not well-formed XML.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference