Relation dynatrace applications - business transactions

Problem:

I searched into the documentation but i do not completelly understand how to deal with applications in combination with business transactions,

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APPLICATIONS

Situation:

I have a load test environment,  i need to perform load testing for two teams (R&D + hosting),

also i need to test for each team two product versions / day. (4 test / day)  

Example: Load test component: WebServer

I have a few web services running into IIS (/team/test), each item has an application pool.

FT_RND (R&D team, fieldtest version)

FT_ASP (Hosting team, fieldtest version)  

PR_RND (R&D team, production version)

PR_ASP (Hosting team, production version)  

Purpose:

Create applications for a single webservice (= FT_RND/FWS, FT_RND/IWS, FT_ASP/FWS, FT_ASP/IWS, ...)

Create applications for a group of webservices (= FT_RND, FT_RND, FT_ASP, FT_ASP, ...)

Create applications that contain all webservices

Create dashboards (business transactions) for all the applications, example show all web calls for FT_RND/FWS application.

In fact i try to make a new relic dashboard into Compuware (we changed to Compuware recently).

It is possible into new relic to choose a product component or product group and view stats on that.

I taught i needed the Compuware application feature to do that. 

New relic:

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How did i try to do this?

Create application, Filter on URL part (single webservice / group) to create applications,

Example: Group on PR_RND (all webcalls from R&D production version)

Queston:

Dynatrace forced me to create a business transaction, what is the reason for that?

To know in what way to present all the calls when i double click on application? Example split calls on soap action? (just trying to understand things)

Some applications does not contain requests?, example PR_RND_FWS has no data but it is a part of PR_RND which has data?

Queston:

Do i need to use application url filter?, can i not just use a business  transaction (example split request on first url tag, sensor, ...)

to create applications ?

Extra example:

I need a application for a WCF web service which works  as a service (accessible through tcp),

the entry point is a dynatrace sensor, so i need to create an application based on a business transaction (with sensor).  

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BUSINESS TRANSACTIONS

When i create a business transaction, i see a defined application name,

Correct?

Business transaction are always executed on applications,

(i remember once a report with web call A & application A  + web call A & application B (i had all de calls double))

So i fact i can create dashboards and the user just selects the aplication by using the filter symbol. 

I guess i do not completely understand how to work with applications in relation to business transactions or otherwise, 

Thx