"We're trying to connect the two. The purpose of the [Taupo] service is to allow people to express their grief and the Taupo community to reach out to the Aim family," he said.
The memorial service has been planned with the help of Ms Aim's family, who have provided a half-hour video presentation about her life which will be played before the service begins.
A piper will lead mourners into the church, and a pipe band will play at her funeral at the East Mainland Parish Church in St Mary's on the Orkney Islands.
Mr Howell has written a prayer about courage that he plans to read, and he said the service in the Orkneys would include a prayer "asking for forgiveness for the person or persons who murdered Karen".
Ms Aim's aunt, Violet Perfect, and her flatmates, Lisa Hughes and Collette Martin, are to speak at the Taupo service, and Christine Rob of the Lava Glass glass-blowing studio, where Ms Aim worked for a month, will talk about a glass vase that has been made in memory of the young woman.
It is hoped those who attend the service will provide donations to send the vase to Ms Aim's parents, Brian and Peggy, and her brother, Alan, who has asked that music by Queen be played for his sister.
A steady stream of people continue to file past the site where Ms Aim was found lying in a pool of blood on January 17, leaving flowers and notes of condolence.
Police have said it is likely to be several weeks before they make an arrest.
The team of 50 officers working on the case has been scaled back over the long weekend.
