dii-ii,
Sorry I put in the code for Chunk due to late night brain fart.
It should be a * for TV and $ for a Chunk as GregR and Anso stated, but I think you probably have that part done correctly, right?
Excuse my ignorance but I spoke too fast without fully comprehending your problem. I personally have not used the Radio Options TV and I assumed you were just not calling the TV correctly, but I went back and tested that TV and duplicated your issue. I see the problem you are talking about which is nothing shows up when choosing that TV type and then following the normal steps for applying the TV where you want it.
After a short bit of searching I found these two links that I think you will find helpful:
http://sottwell.com/tv-input-types.html
and
http://rtfm.modx.com/display/revolution20/Template+Variable+Input+Types#TemplateVariableInputTypes-RadioOptions
and I'm sure there are some more, possibly even in this forum, did you search around here?
With a quick skim over those links it looks to me that if the TV is a Radio Options type you need to provide more information so that MODX knows what information your Radio Button is referencing. You can find the "Input Option Values" box directly under the box where you chose the Input Type and you need values there in the form of:
Read through those links and see if you can figure out what you need to put in for Values. They may not address your specific function in the examples but see if you can apply it to what you are trying to do. I did notice you can target chunks with the radio option for example.
If you're still stuck after you give it a go post back here. Be as specific as you can. The more specific you can be and the more effort you put into working it out on your own the more likely you'll be to get a response from an advanced user who has experience with those functions.
Cheers and GL!