Is this the entire response?
I've seen cases where a PDF has been encoded in Base64 format (which will look like a bunch of letters and numbers). If that's the case, then that can be decoded in SoapUI Using the following groovy script:
def groovyUtils = new com.eviware.soapui.support.GroovyUtils( context );
import org.apache.commons.codec.binary.Base64;
Base64 coder = new Base64();
def timeInMilis = System.currentTimeMillis()
def filename = context.expand( '/invoice' + timeInMilis +'.pdf')
def encodedString = context.expand( '${#TestCase#base64Text}' );
def decoded = encodedString.decodeBase64();
def f = new File(groovyUtils.projectPath + filename);
f.delete();
f << decoded
log.info(groovyUtils.projectPath + filename);Assuming you have a test case property called base64Text (where you've extracted and stored the encoded data) this code will decode the rest for you, and save it as a PDF file.