Get own taskid before workitem creation in deadline monitoring

[Thomas, Theo]

The deadline monitoring tab latest start contains : &ZDEADL.DEADLINE&
DEADLINE is a virtual attribute in an object we created.
 
The DEADLINE attribute computes the deadline based on several variables.
I also need the TASKID (TSxxxxx) so I can look up in a table the nr of days to add to the deadline depending on the taskid.
But: I can not use _WORKITEM because the workitem is not created yet.
How can I get the TASKID ???
 
Met vriendelijke groeten / Best regards,
 
Theo Thomas
Consultant Technical Services
SAP Nederland B.V.