XPath substring in Receiver Determination

Hi Guys,

I have a business case in an Idoc to File PI Interface wherein, I want to export a file if and only if the 14th caharcter of an Idoc field is not equal to "|" and I am trying the following conditions in XPath Receiver Determination, but none of them is working:

/ZMDPU_ORDERS05/IDOC/E1EDP01/E1EDP19/IDTNR[not(substring(.,14,1) = '|')] EX

/ZMDPU_ORDERS05/IDOC/E1EDP01/E1EDP19/IDTNR[substring(.,14,1) != '|'] EX

The opposite, is working just fine though, i.e. 14th character of the Idoc field = "|":

/ZMDPU_ORDERS05/IDOC/E1EDP01/E1EDP19/IDTNR[substring(.,14,1) = '|'] EX

Therefore, the issue seems to be in the syntax of NOT function. Any ideas?