I've investigated a byt further the issue, and seems there is no solution using mango 1.13 or ScadaBR.
To decode the numbers represented in the above standards it is necessary to swap dwords words and bytes, so in the case I described I was right
The words are 0f55 2102 to obtain the corrensponding decimal value one should first of all swap words
0f55 2102 ==> 2102 0f55
then swap bytes 2102 0f55 ==> 0221550f
then convert to decimal 0221550f => 35738895
So, If I need to read a double made this way (starts from register 8 ends on register 11)
8 ==> 9418
9 ==> 0456
10 ==> ae98
11 ==> c240
first of all I should swap dwords words and bytes this way ==> 40c2 98ae 5604 1894
then I should convert it using the IEEE-754 standard for 64 bits, and the resulting number is 9521.362000000001 wich is right.
This is too much complicated to do, so I have to give up with reading this piece of hardware.