[rt-users] RT worklfow with approvers, chosen from list

[zux]

Hi,
i have been trying to create a workflow, i'll try to describe it here:
User A from group HR creates a new ticket in queue "New employee".
User A chooses a value from a custom field called "Manager", this is a 
"Select one value" custom field with a drop down.
The values in custom field "Manager" are usernames of managers.
Now i would like to create an approval ticket, with owner - custom field 
"Manager" value.

I have tried, without success, this code in template:

===Create-Ticket: Jauns Darbinieks
Subject: New employee  {$Tickets{'TOP'}->Subject}
Depended-On-By: {$Tickets{'TOP'}->Id}
Queue: ___Approvals
Type: approval
Owner: {$Ticket{TOP}->FirstCustomFieldValue('Manager')}

I get this error:
Owner: Can't call method "FirstCustomFieldValue" on an undefined value 
at template line 6.

How do i correctly forward the value of that custom field?

The question also relates to the next part of my workflow. After the 
manager approves the ticket, i would like to create 2-3 more tickets. 
And each one of them would need to get some custom fields from the 
parent ticket (but not all)
something like this - It would get a ticket with the username and what 
computer should be given
security would also get a ticket with info about access restrictions
accounting would get some other info, that security and it should not be 
able to see

How do i correctly forward these custom fields to children tickets?