User Driven Installation - required steps in Task Sequence

Hi,

I am testing deployment of the OS, so that we can take the advantage of UDI. We have a duplicate of a production Task Sequence, that is used for testing purposes. We are using SCCM 2007 R2, we have installed MDT 2012 U1 in order to use UDI solution.

In the duplicate of a production TS, I have added few steps for UDI:
TS starts with remapping CD drive, then I have added below:
1. Use Toolkit Package
2. Gather
3. UDI Wizard [The UDI wizard opens, I can select apps to install. All goes fine. UDI xml file is modified, it has only page to Install Programs]
Now, next steps of TS applies Win7 x64, installs drivers, joins domain, sets up ConfigMg, executes few scripts to install software updates [software included in the image, like MS Office].
All above steps are done with no errors.
Now two more steps I have added:
4. Gather
5. Install Software

And on 4. throws error:
Failed to run the action: Gather.
Incorrect function. (Error: 00000001; Source: Windows) TSManager 2013-07-12 11:03:43 2108 (0x083C)

and on 5.:
The execution of the group (Install UDI Apps) has failed and the execution has been aborted. An action failed.
Operation aborted (Error: 80004004; Source: Windows) TSManager 2013-07-12 11:03:43 2108 (0x083C)
Failed to run the last action: Gather. Execution of task sequence failed.
Incorrect function. (Error: 00000001; Source: Windows) TSManager 2013-07-12 11:03:43 2108 (0x083C)


The question is, what steps in TS does the UDI require in order to install the Apps correctly? We cannot create new MDT TS with, as this would mean we need to adjust new TS to our needs and spend many days on testing.

We only need to add UDI steps to existing one. Basically UDI is a Run Command Line TS step.

Many thanks in advance!

Marcin