Cannot send a delayed BYE to caller

[oferbar]

Hello,

I am using SIPp v3.5.2-SCTP-PCAP-RTPSTREAM, with a custom configuration based on: uas.xml.
Normally, the caller is sending an INVITE and then a BYE to terminate the call.
However, for testing purposes I am trying to send a BYE from the server after X seconds.
I added an unused attribute in the INVITE header, and then parse it during the INVITE in the Xml.
If I get the header, a conditional is doing and .
However, that section does not work, although I verified that the condition is met with logs.

Bottom line, what is the best way to handle such a case inside SIPp?
So far, everything I tried did not work.

Here's some code snippets:

INVITE:

Pause & BYE:

Thanks