Hi Alexy,
Philip and I did analyze mapper support for properties NB build
sierra_481_20080909_0002_dev. Here are the observations.
1. When we map from variable property to variable property it
generates right ws-bpel code and renders it accurately.
<copy>
<from variable="ConcatTestOperationIn"
property="ns0:str1Prop"/>
<to variable="ConcatTestOperationOut"
property="ns0:str1Prop"/>
</copy>
2. When we map from variable property to a target node on a variable.
It generates right ws-bpel code, but render it with warning in design
view. Note that tool tip on property is not showing the property type.
<copy>
<from variable="ConcatTestOperationIn"
property="ns0:str1Prop"/>
<to>$ConcatTestOperationOut.concatPart/str1</to>
</copy>
3. I am able to use property in an expression as shown below. The
prefix for the property name is missing in the generated code. It does
not retain this view when I switch back to mapper.

<copy>
<from>concat(ns1:getVariableProperty('ConcatTestOperationIn',
'str1Prop'), ns1:getVariableProperty('ConcatTestOperationIn',
'str2Prop'))</from>
<to>$ConcatTestOperationOut.concatPart/str1</to>
</copy>
Do we need "GetVariableProperty" function node? We feel it is not
required.
Now on NM property, user experience should be same for NM property
except that we should not list them by default unless user uses them
in the mapping.
Regards
Murali