Currently, the only possibility is to use the component name of the symbol. I.e. for the example above:
In the “model” field, replace the second token “SP” with “_15SQ47N_”.
Note that a component name must not begin with a digit, therefore the underscore at the beginning. And the schematic editor will append a number at the end in order to make the string unique, therefore the underscore at the end (for better readability).
Good luck!