BPEL assign count and node value from xml

Question

I have mapnames.xml in the project with nodes like this:
<mapname>STATUS_DIMS_LOAD</mapname>
<mapname>MOVEMENT_DIMS_LOAD</mapname>
The xml of mapnames will be used for an input variable for a FlowN invoke.
Trying to count the number of mapnames in the xml document and put in a variable.
<assign name="getMapNamesN">
<copy>
<from expression= *"count(bpws:getVariableData('... ? " />*
<to variable="FlowN_Dims_Count"/>
</copy>
</assign>
Then use that in the FlowN
<bpelx:flowN name="FlowN_Dims" N="bpws:getVariableData('Flow_Dims_Count')" indexVariable="Index">
And then inside the FlowN, get the actual mapname using the index.
<assign name="Assign_Dims">
<copy>
<from expression= *"bpws:getVariableData('... ? [',bwps:getVariableData('Index'),']') " />*
<to variable="Invoke_Dims_InputVariable" part="InputParameters"
query="/ns8:InputParameters/ns8:P_MAPNAME" />
</copy>
</assign>
What is the syntax to
1. Count the number of mapnames in the xml document?
2. Use the FlowN index to assign the mapname to an input variable?

Answer 1

That looked hopeful, but it did not show how to create the variables and I do not know the syntax for making an array variable.