silhouette plot of similarity matrix

Hi, I have 1000 matrices of size Nx3 where N is not fixed and varies between matrices. The columns of the matrices are corresponding to x,y, and z coordinate so basically each matrix stores the spatial coordinates of some points in the 3D space. I used dtw() to create a similarity matrix (X) between all matrices so it gives me a similarity matrix of size 1000x1000. Then I use kemansX,10) to cluster the similarity matrix to 10 clusters. Now, I need to evaluate the clustering and want to use silhouette command. My question is that how I can use the silhouette() command here? the Matlab help says that the input to silhouette is a matrix that each row is a point and each column is a coordinate but here I have a similarity matrix which is not a point coordinate matrix anymore.

Thanks,