byte[] serializing to inefficient array

[Grant Hulbert]

I am using Axis/Java to return a struct as follows:

public class ImageStruct {
        public  int             imageID;
        public  String  imageName;
        public  byte[]  thumbNail;
}

My problem is that instead of the byte[] returning a single base64 element, I get an 
array of thousands of

   <thumbNail xsi:type="xsd:byte">-1</thumbNail>
   <thumbNail xsi:type="xsd:byte">-40</thumbNail>
   <thumbNail xsi:type="xsd:byte">-1</thumbNail>

I've returned byte[] from simple .jws files before, and they serialized as the 
more-compact base64 automatically.