Cannot use "shape symbol" I just draw

I am new to Cadence software. I have to create a custom footprint for a component. One pad has an arbitrary shape, so in the `padstack editor` tab `design layers` I click on the `...` button next to `shape symbol` and then in the `library shape symbol browser` window that pops up I click on `create new shape symbol`. Then I draw the pad and saved it in `/path/to/somewhere/my_pad_shape.dra`. 

Now I go back to the `padstack editor` tab `design layers` and I click the `...` button again. In the `select a pad symbol from the list` field, my newly created pad does not show up. 

How can I use `/path/to/somewhere/my_pad_shape.dra` in my padstack?

PS: I cannot upload images to this post because "An error occurred. Please try again or contact your administrator.". I could ask my question in a more human friendly format if this would work, my apologies.

EDIT: From [this tutorial](https://www.youtube.com/watch?v=l-HPPbLyKsc) I see the file is somehow saved as `.ssm`. In my case, it is saving it as `.dra`.