||The feature you're asking for is commonly known as a tag line and Poco does support it.
You don't even need a script to do this, check out the common variable tags that can be inserted in signatures.
Add the following line to the bottom of any signature that you want to add a tag line to.
where you replace "filename" with the name of the file containing your tag lines.
You can even insert multiple line tag lines by adding entries of the form:
to your tagline file. When such a line is selected Poco will read the corresponding tag line file and
insert all the text from it as the tag line, including line breaks.