Hi Leonardo,
Firstly no - Business Client is not needed.
Ok so your source UWL XML file is using the OBN Launcher rather than the Web Dynpro ABAP launch mechanism. So you are comparing apples to oranges there.
Your second attempt using SWFVISU in SRM is closer.
It looks like the Web Dynpro Configuration id has not been passed.
What I would suggest doing at this point is trying to start the application and configuration directly from transaction SE80 using the Test option there. That would help you clarify the exact URL you are trying to launch and with what parameters.
There will be a parameter to pass the work item id - it's possible your SRM version does not use the standard _WI_ID parameter in which case you may need to set up the SWFVISU Task Visualization Dynamic Parameters after all. You can also use Dynamic Parameters to pass the Web Dynpro Configuration if need be.
Rgds,
Jocelyn