Scenario: In this Blog i will call the SAP CRM Transaction BP via the CRM Web UI using button. Just you have to follow the below mentioned steps.
Step 1: Go to transaction CRMS_IC_CROSS_SYS for Checking Logical System and URL.
In this case we are planning to execute the launch transaction in our own system as shown in properties below.
Step 2: Add the button code and launch transaction calling code in .htm page of view as shown in below screen shot.
Here i have added a button using in the htm page of the view and on the event handler i have set a flag in the IMPL class. based on the value of this flag corresponding call to the URL is made in an frame on the same page.
This opens up the BP Transaction in an iframe in the same view. To open any transaction, replace IC_LTX in the URL with the required transaction.
Layout Code :
%--Button Code --%>
<% if controller->open_clicked ne 'X'. %>
<thtmlb:button id = "OPEN"
design = "EMPHASIZED"
onClick = "OPEN"
text = "OPEN BP Transaction"
enabled = 'true'
/>
<% endif. %>
%-- Event Handler Code --%>
<% if controller->open_clicked = 'X' . %>
%-- This URL is taken from transaction CRMS_IC_CROSS_SYS --%>
<% controller>url = '"http://xxxxxxxxx/sap/bc/gui/sap/its/webgui/!?~transaction=BP&~okcode=ICEXECUTE&sap-client=800"'.%>
%-- Launch Transaction Design Code --%>s
<html>
<iframe name = "ff" id ="ff" width = 900 height = 900 src = <%= controller->url . %> >
</iframe>
</html>
<% endif . %>
Step 3:Create Event for this view and add the following code in event handler method as shown in the screen shot below.
Step 4: Double click on the Implementation class of TransactionLauncherOnButton view and add the two attributes OPEN_CLICKED and URL as shown below.
Step 5: Save,Activate and Execute the component .
Step 6: When click on OPEN BP Transaction button, set flag and capture its value in the HTM page of the required view.
To find Business Partner through Launch transaction
It will helpful for who are struggling launch transaction in this type 
.
Thanks & Regards,
Harikrishna M.