Hi Indrajit!
Oh that is fantastic news and never heard of that before! I hope it works and if it does then please share with us the details.
Out of curiosity I installed XAcars and played with it offline yesterday and today and finally got it to submit a pirep. I see exactly the same results as you so it is an issue with the XAcars client itself. If that XPUIPC plugin works and you can get CVAcars working then that will be so much simpler and I am curious to know how that works out!
We can create a new forum specific to XPlane users as it seems this will become more popular moving forward and so having a dedicated forum to that is a useful place to put this and other future info as it relates to XPlane.
Look forward to hearing / seeing your results!
Cheers!