How to extract a text from a workflow "string" process property

Hi,

We have a web service in production that sends opportunities in Siebel. A siebel WF is used to receive the web service message and create the opportunity.

That web service will provide a block of text that will be stored in a WF process property (data type = String)

That block of text contains different data that are separate by a pipe character. Example:

|string 1|string 2|string 3|string 4|

I need to store "string 1", i.e. the value (which can be null) between the first  two pipe characters in another WF process property (data type = String) for further processing.

Because I cannot change the SRF right now, I need a solution that is only workflow based using vanilla business service.