System.ExpressionFilter ContainsSubstring $target/ or $Config/...

Question

Hi
Is it possible to filter if a $target/... or $config/... expressions is contained by a String? I've tried to pass the $target/... directly to the pattern tag, but the workflow does not resolve the variable.
Other tries with Value Expressions failed as well.
Here the output from MPSimulator:
08.04.2014 15:44:17 ExpressionEvaluatorCondition FilterEvaluationTrace Filter Instance (0000000000F3AFA0): Evaluating RegEx Expression:
    <ValueExpression>
        <XPathQuery Type='String'>EventDescription</XPathQuery>
    </ValueExpression>
    <Operator CaseSensitive='false'>CONTAINS_SUBSTRING</Operator>
  <Pattern>$config/customstring1$</Pattern>
Resolves to:
  Site path: C:\inetpub\wwwroot\Citrix\XenApp.
All the Citrix XML Services configured for farm Farm1 failed to respond to this XML Service transaction. [Unique Log ID: a329c0b1]
For specific information about this message, see the Web Interface documentation at[link to citrix]
    CONTAINS_SUBSTRING
  $config/customstring1$
Using case insensitive string compare
RESULT = NOT A MATCH
... i set the $Config/CustomString1$ to 'C:\inetpub\wwwroot\Citrix\XenApp'.
Thomas

Answer 1

Hi Jonathan / Vladimir
<Expression>
 <RegExExpression>
  <ValueExpression>
   <XPathQuery>EventDescription</XPathQuery>
  </ValueExpression>
  <Operator>ContainsSubstring</Operator>
  <Pattern>Citrix</Pattern>
 </RegExExpression>
</Expression>
-> It's working
<Expression>
 <RegExExpression>
  <ValueExpression>
   <XPathQuery>EventDescription</XPathQuery>
  </ValueExpression>
  <Operator>ContainsSubstring</Operator>
  <Pattern>$Config/CustomString1$</Pattern>
 </RegExExpression>
</Expression>
While CustomString1 = "Citrix"
-> Not working
Same Result with Regular Expressions
<Expression>
  <RegExExpression>
    <ValueExpression>
      <XPathQuery Type="String">EventDescription</XPathQuery>
    </ValueExpression>
    <Operator>MatchesRegularExpression</Operator>
    <Pattern>^.*(Citrix).*$</Pattern>
  </RegExExpression>
</Expression>
 -> working
<Expression>
  <RegExExpression>
    <ValueExpression>
      <XPathQuery Type="String">EventDescription</XPathQuery>
    </ValueExpression>
    <Operator>MatchesRegularExpression</Operator>
    <Pattern>^.*($Config/CustomString1$).*$</Pattern>
  </RegExExpression>
</Expression>
-> not working
The lowercase from your answer above ist just the output of MPSimulator...
It really seems, that my $Config/CustomString1$ is not resolved.