I got the answer!
At the last International ABBA fanclub day one of the special guests was ABBA's very own costume designer Owe Sandström. He brought with him a lot of stage outfits.Awesomee!
Also I finally had the opportunity to ask a question that had been on my mind for years: why did Frida wear the kneelength pants during the European part of the 1977 tour and the ultra short shorts during the Australian part?
According to Owe the answer was quite simple. Frida liked to change ( well what do you know ;-) and she asked him to make the shorts. She simply wanted to expose herself!They brought along the knee lengths at the Australian tour but she never wore them.
During an interview (also in Australia) Frida told the journalist that she loved to be on stage: she called herself an exhibitionist.
excuse me but...
Look at me!
Look at my legs!