I have a Magento product page producing static select elements, to which the price mechanism is tied in to backend, so i can't touch those dropdowns. I am using an angular.js radio element to recieve user input, which should in turn update the static dropdown's selected option.
I don't know how to link the two, I have recreated the problem here: http://jsfiddle.net/ldn_tech_exec/smBdC/1/
I want the radio button to update the dropdown, but I can only manipulate the dropdown after it has been created, perhaps using jquery to insert any angular directives required.
UPDATED again: Your select list needs an ng-model and the options should be generated with ng-options. When you select a radio button, the controller method you trigger should update that ng-model, which will cause the select list to update. See http://docs.angularjs.org/api/ng.directive:select
Another way to do this is to use ng-selected. See http://docs.angularjs.org/api/ng.directive:ngSelected
UPDATE #3: I missed the fact that you can't modify the select list initially. See my fiddle in the comments below for a working solution.
It sounds like you have some product where the price depends on the options set.
If this is the case then updating the drop-down from your radio button is relatively trivial - or at least depending on your prototype/jquery skills.
However there is a gotcha: once you update the drop-down in javascript with an 'invisible hand' there is a whole lot more javascript code to update the price and availability. To do this you need to bubble the event. This doesn't happen automatically if using prototype.
I hoped I could rustle up the 'bubble code' but I don't currently have it to hand, besides, you aren't stuck at that point, yet...