Dynamic " to " in assign not allowed?

Question

I am doing an assign that essentially looks like this:
<assign>
<copy>
<from expression="some other value"/>
<to variable="var" part="payload" query="/ns1:list/ns1:listElement[@myValue=bpws:getVariableData('123')]/@myOtherValue/>
</copy>
</assign>
I get the following build error (para-phrasing):
ORABPEL-09707
Failed to initialize variable. Could not initialize variable "var" @ line (whatever)
I looked at the spec and it only states that it the query is XPath 1.0 and resolves to a single node.
I validated my xpath in XMLSpy...so either this is a limitation or I am doing something else wrong?
Cheers,
-Dustin

Answer 1

Again, sorry for not describing my problem well enough...I gave the impression that the "Assign_2" is happening synchrounously and a single time. The use case is:
1. Process A is orchestrating many synchrounous/asynchrounous activities with several other processes (XX,YY,ZZ, etc.) as part of its request to perform an operation.
2. process A (which is long-running) is maintaining an in-flight data structure representing the result bits of the various completed services. Other services/processes are invoked based on results of intermediate service steps (or combination of intermediate results).
3. For each service completed, the inflight data is updated, but which part of the update depends on the service result (as A will have many instances of a single process to do work).
This results in the need for dynamically updating the list. In reference to your sample, I do not know the value '123' in Assign_2. That is why I was using the getVariableData function. I can do this in the <from> part but not the <to> part.
I am building a sample now to send to you. Hopefully that will clarify.
-Dustin