You'll need to modify Win32::CommPort. It contains a table of what it believes are the valid values for baudrate: 

COMMPROP=> [
    qw( BAUD_USER   BAUD_075   BAUD_110
        BAUD_134_5  BAUD_150   BAUD_300
        BAUD_600    BAUD_1200  BAUD_1800
        BAUD_2400   BAUD_4800  BAUD_7200
        BAUD_9600   BAUD_14400 BAUD_19200
        BAUD_38400  BAUD_56K   BAUD_57600
        BAUD_115200 BAUD_128K

[download]

You'll need to add the value(s) that you are trying to set to prevent it from rejecting the attempts.

There is also a second table of baudrate-like values just below that may need updating also.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re: Win32::SerialPort faster connection than 115200 baud by BrowserUk
in thread Win32::SerialPort faster connection than 115200 baud by LotharWerner

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