I don't have much experience with RFT, but I've used other adapters and found this question interesting so I did a little research. I found that you CAN pass arguments from RQM to the RFT script. When you create a script in RQM and specify the type to be RFT, there is a section at the bottom of the RQM script editor titled "Script Arguments". This is where you specify arguments to be passed to your RFT script.

Here's a page in the RFT InfoCenter that talks about the different argument types:

http://publib.boulder.ibm.com/infocenter/rfthelp/v8r1/topic/com.ibm.rational.test.ft.doc/topics/r_handling_rqm_details.html

In your RFT script you will need to insert either a Java Snippet or Java Method in order to access these argument. They will be passed to the testMain() method of your RFT script, which can be accessed on the "Java" tab of the RFT script editor. More info on RFT Java Snippets is here:

http://publib.boulder.ibm.com/infocenter/rfthelp/v8r1/topic/com.ibm.rational.test.ft.doc/topics/t_insert_java_code.html

RQM doesn't give you the option to specify different arguments at the test case level, instead it is done at the test script level. But there's no reason you can't create multiple RQM test scripts that point to the same underlying RFT script but supplies different arguments. To do this in RQM, go to view test scripts, select the script you are interested in and hit the duplicate button at the top of the list. Or just do "Create Test Script" multiple times. But don't use "Import Test Script" because the import wouldn't import the same script twice.

Additionally, you may try posting this question on the RFT forum as well. That forum is located here:

http://www.ibm.com/developerworks/forums/forum.jspa?forumID=322