Yes, your files are in the Pronto Hex Format. The Ir signals are Nokia32 IR protocol, device 32, subdevice 192. The X field is either 38 or 166-- note that 166-38 = 128. The most significant bit of the X field is the toggle bit.

Here for example is digit 9 (which has a function number of 9)
20C0A609 (hexadecimal format)
20 = 32 Device
C0 = 192 Subdevice
A6 = 166 X
09 = 9 Function number
I believe that MediaPortal has support for the Nokia protocol (usually seen in 12 or 32 bit versions, and this one is 32 bits.)

General support for Nokia would include the possibiity to keep the toggle bit fixed, to alternate it with each button press, or to flip it on repeated signals when the button is released. I believe, based on the fairly small set of learned sgnals, that the Pace box uses an alternating toggle bit.

So I hope that you can figure out how to use MediaPortal to send these signals with correct toggle behavior.  Below are function codes from a Pace DC-621KU STB, which match your codes for 0-9 and Select.

You can use IRScope to see the decodes of each of your IR files, using the Import button.  Highlight each imported code to see the IRP notation for the signal and look at the part starting "A=".  If the following string contains 8 hex digits, then that is the exact decode.  If there are 16 digits, it is an erroneous decode.