DTD line in incoming payload issue with interface determination condition

Hi,

I have SAP PI 7.3 single stack.

Scenario is HTTP to HTTP.

In the incoming request -

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE cXML SYSTEM "http://xml.cxml.org/schemas/cXML/1.2.024/cXML.dtd">
<cXML >

<A>avalue</A>

<B>bvalue</B>

</cXML>

the interface determination condition i have put based on value of node A and node B. But due to line mentioned in RED above,it fails in interface determination condition.

we can't change the incoming request format. Is there any way that the RED line gets removed from input XML and interface determination condition is also retained.

thanks