Whitespace problem in XML

Having a problem with the IBM SAX parser (which is Xerces).

We have the data comming from a client that looks something like this:
<tag>
A string of about 300 characters containing an embedded null
</tag>

Now when our Java servlet parses this we have a character method that does this:
public void characters(char[] ch, int start, int length)
{
String s = new String(ch, start, length);
.
.
.
And we get an SAX parser error on the column containing the null (Unicode 0x0).

What is the best way to handle this? I don't think ignorable Whitespace solves the problem since that seems to handle elements that are entirely whitespace. Any help is appreciated.