xsd:boolean element type accept "true" but not "True". How can I make it accept it?

I am using xmllint --schema option to validate my XML that looks like this

<XML>
<Active>True</Active>
</XML>

In my schema file, I have following line that describes Active element.

<xsd:element name="Active" type="xs:boolean" />

When I run xmllint, I get error messages that says

/tmp/schema_validation.xml:73: element Active: Schemas validity error : Element 'Active': 'True' is not a valid value of the atomic type 'xs:boolean'.

When I change the XML to

<Active>true</Active>

Then the error message disappears.

So, it looks like xsd:boolean means it's all lowercase "true/false" but not "True/False" to xmllint.. My question is, how can I make xmllint to accept "True" for xsd:boolean type? Or is there different tools that I can use that will validate this XML? Changing the XML or schema is not my option at this point.

Thanks!