This has been nicely explained in a friends blog. Below is the description.

The first question arises , why we need XSLT transformation, so here are some reasons -
- Suppose sometime we have the data in XML file but we want to present it in different ways depending on its contents.
- Or we need to read data of a email template from a file and email needs to be with colors, tables and more HTML look.
- Or when our email data is coming from different BCs or calculations in a Business Service, or Property Sets, and we are not able to use Siebel …

EAI Queuing is one of the Siebel integration tool to capture the SiebelMessage in a Integration Workflow in case the Workflow Errors out.
For more details, follow below link as I have already posted redarding this there -
http://www.siebelintegration.com/SiebelInterviewForum/index.php?topic=8.msg8#new
Post your comments in case you find any difficulty in getting it.

When we want to expose Siebel functionality to other non-Siebel applications, we create Inbound Web Service and expose Siebel functionality either by a Business Service or a Workflow. We can expose these entities as Web Services. Once you have created a Web Service and generated the WSDL file, you need any third party application to do a live test for the Web Service. SoapUI is a nice software and freely available to test Web Services.
Below are some steps to get SoapUI and make it ready for testing. You can test …

1. Create a new record and give the business service name as the name of Proxy Business Service: CurrencyConvertorSoap, pick its method.
2. In the middle Input applet, click Load From File button to browse the Inputs file [WebService-Inputs.xml] which we created in the above process. This will load input Siebel message. Navigate inside the mvg at Child Type and give the From and To Currency names like USD and INR
Inputs – From and To Conversion Currencies.jpg
IMPORTANT:
Now you need to modify this message a bit, Click the Child Type mvg …