This should be possible. But it may take you some time to study both the ttx format and the volt project file format and then write a tool that does the conversion.

i hope some day, a good man would do that job.... thnx

It is not a question of goodness. You are talking about a considerable amount of work. And your question actually is: Could anybody please do my work? Short answer is: No.

Obviously Microsoft did not find it useful to import OT fonts' layout tables back into VOLT so they did not add an according function.
If you plan to add more features to your own fonts, you should still have the original VOLT fonts or project files, so that you can adjust these.
But if you need a tool tailored for your own special workflow, as is my impression, then it would have been more appropriate to say how much hours, days, weeks of work the tool would save you and thus what it is worth to you, rather than appealing to goodness.

Well put.