F4 not working on pda. Additional key possible?

[Hhvh]

Hello, thanks for developing such a useful utility.
I'd like to use it from an old pda. I can access it trhough the pda's web browser, and all's working fine, but... I can't send the text to the smartphone, because in my PDA, F4 has already another function assigned.
Would it be possible to assign the "submit" funtion to another key, such as ctrl+...?

Thanks