Message Mapping Split

Hi,

following task is 2 high 4 me:

<root>
   <fieldA/>
   <fieldB/>      optional
</root>

should be mapped to

   
<root>
   <elm>
     <constant>A</constant>
     <value>A</value>
   </elm>
   <elm>
     <constant>B</constant>
     <value>B</value>
   </elm>
</root>

If only field A exist then only one result elm.

If field B exist then two result elm.

Any ideas?

Udo