Arsenal manager Arsene Wenger feels loan deals should be treated just like permanent transfers.
Fabricio Coloccini has re-affirmed his commitment to Newcastle amid fresh speculation that he wants to leave.
Newcastle have made an offer for the Brazilian-born 24-year-old, who is close to securing Dutch citizenship.
Premier League rivals Fulham and West Ham United have also been linked with a bid for Douglas, while reports in Holland claim Aston Villa and Wolfsburg shelved interest earlier in the summer.
Douglas, however, appeared to muddy the waters earlier in the week when he said that he was unaware of an offer from Newcastle and that he wanted to stay at Twente.
Munsterman, though, appears to be becoming a little exasperated by the situation after conceding he does not know what either Newcastle or Douglas are looking for.
"It is unclear what Newcastle United and Douglas want exactly," Munsterman told De Telegraaf.
"Douglas says he wants to leave one week and the next week he wants to stay."