Yes, but its not all that fun
There are several documents that tell about the Pronto format. Armed with those and the RAW format details you have what you need to do it manually. If there's enough interest I can probably be pursuaded to put this into the Girder plugin or some sort of utility.
The RAW format you see in Girder is very simple: It always begins with 'R' to indicate RAW. The next 4 digits are a hex value of the delay value between codes. Pronto handles this delay by making it the last PAUSE of the last burst pair.
Following these is the actual burst data, starting with the initial burst. Each burst or space is represented by two *or* 4 digits. Two will be used if the duration is less than 0x80 cycles long. If the dureation of the burst or space is >= 0x80, then 4 digits will be used to extend the duration to a 15-bit value (with the MSB bit 15 set to a 1).
The RAW format does not require bursts and spaces to be paired -- ie., the sequence can end with a burst -- and often does. When converting this to a Pronto code you would take the Inter-code Delay value and make it the final space.
The timing value for bursts and spaces is similar to Pronto -- each value is in carrier cycles. The *exception* is the inter-code delay value, which is in units of 51.2uS.
The last detail is if there is a code in the 'Code2' box, then this would be the 'repeating' code and the code in the 'Code1' would be the 'once' code. The 'Code2' box's contents in this case will not have an 'R' in front.
-Jon