Use tib:evaluate
instead of dyn:evaluate
.
Depending on what else your BW process contains, you may need to add the namespace below to the process in order to use the tib:evaluate() function:
namespace=http://www.tibco.com/bw/xslt/custom-functions
prefix=tib
To do that you would select the process, click the "namespace registry" button, and add the namespace above.