I found some clues that most, if not all, bryozoans can reproduce and multiply by asexual and sexual means, for example:
Thomsen & Hakansson 1995: "Sexual Versus Asexual Dispersal in Clonal Animals: Examples from Cheilostome Bryozoans":
Bryozoans are purely modular and, like corals and other colonial animals, they multiply both sexually and asexually. Conventionally, increase in colony size (growth) is believed to occur through asexual budding of additional modules, whereas new colonies are established by settlement of sexually produced motile larvae (reproduction).
It seems that other reproductive mechanisms, such as storing sperm, are universal among this phyla (Bishop & Pemberton 2006), so I wouldn't be surprised if this is also true for combined asexual and sexual reproduction. However, the phyla contains a lot of species, so exceptions wouldn't surprise me either. The cited source is also almost 20 years old.
Is there any evidence that some Bryozoan species do not reproduce asexually and sexually? If so, in what order or class do they fall? If it helps, I'm most interested in the Cheilostomatida.