I like this idea.
As far as how you write it into the IEP, if it's just "let her use AT as an alternate means of demonstrating mastery of the standards", then it's an accommodation. An IEP goal/objective would use specialized instruction to teach her to use the AT proficiently and independently, in order to make effective progress in the curriculum frameworks. Some possible objectives, more or less in increasing order of complexity:
-working with DD, identify AT hardware and software that is appropriate to her needs.
-with support, acquire proficiency in basic functions of the identified AT.
-demonstrate independent proficiency in basic functions of the AT.
-with support, expose DD to advanced functions of the AT.
-with support, acquire proficiency in advanced functions of the AT.
-independently demonstrate proficiency in advanced functions of the AT.
(You might consider naming some of these basic and advanced functions, and some of the specific types of AT that you want introduced, in the goals/objectives, such as, "demonstrate proficiency in AT, including but not restricted to tools for creating, editing, and publishing audiovisual presentations that document mastery of the standards".)
