Also, I need to get the namespace from the input
document and put it into the root element.
For example the input root document :

<manifest xmlns:ex="http://www.exercise.com"
xmlns:adlcp="http://www.adlnet.org/xsd"/>

the desired output (added namespaces in the root
element)
<Metadata
xmlns:ex="http://www.exercise.com"
xmlns:per="http://www.adlnet.org/xsd">
....
</Metadata>

How do I add this namespaces, since I can't do it
manually?Which xpath that access the root and tell it
to add the namespaces?

<xsl:stylesheet
 xmlns:ex="http://www.exercise.com"
 xmlns:per="http://www.adlnet.org/xsd"

Then just create the <Metadata> element and the namespaces will be
added for you:

<xsl:template match="/">
 <Metadata>

<Metadata xmlns:ex="http://www.exercise.com"
 xmlns:per="http://www.adlnet.org/xsd">

cheers
andrew