Converting .apk files to .sisx format.
An .apk to .sisx conversion is not possible since you can't convert Android Package Files (.apk) to Symbian OS Installation Files (.sisx).
Android app formats cannot be directly converted to Symbian format. Check the website of your Android app's developer if a Symbian version of your Android app is existing.
In a word, direct apk to sisx conversion is not possible.
So don't expect any so-called apk to sisx converter or apk to sisx free online conversion tool available.
The database currently does not contain any apk software converter.