Question: Base64 Transform Nodeset Input

What does section "6.6.2 Base64" mean whan it states:

"If an XPath node-set (or sufficiently functional alternative) is given as 
input, then it is converted to an octet stream by performing operations 
logically equivalent to 1) applying an XPath transform with expression 
self::text(), then 2) taking the string-value of the node-set."

Is the following fragment valid input which decodes to "The URI of the 
transform is http://www.w3.org/2000/09/xmldsig#base64"

<BASE64>
VGhlIFVSSSBvZiB0aGUgdHJhbn<comment>Inserting this comment should not change 
anything for processing</comment>
Nmb3JtIGlzIGh0dHA6Ly93d3cudzMub3JnLzIwMDAvMDkveG1s
ZHNpZyNiYXNlNjQ=
</BASE64>


Christian