Huh, well this is interesting. This is a REFERENCE guide (Operation OVERLORD) which points to documentation for various units, including the 1149th. The document is called:
Armed Forces Oral History - World War II Combat Interviews
Look at page 46 of this PDF file. It points to the following documents:
CI-370 through CI-372
According to this reference guide, these materials are located at:
Washington National Records Center - Operated by the National Archives (NARA) in Suitland Maryland.
If you can get your hands on this docs....well that would really rock!
The CI stands for Combat Interviews, but as the user guide points out, the documentation includes narrative histories, operation reports, official journals, etc.
I am going to post this reference guide in my RESEARCH section too, since it encompasses a vast number of units. Can't believe I hadn't found this until now. But that is what research is all about. You start out looking for one thing and...
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"