Patterned elements of permalloy (Py) with a thickness as large as 300 nm have been defined by electron beam lithography on X-ray-transparent 50 nm thick membranes in order to characterize their magnetic structure via Magnetic Transmission X-ray Microscopy (MTXM). To avoid the situation where the fragility of the membranes causes them to break during the lithography process, it has been found that the spin coating of the resist must be applied in two steps. The MTXM results show that our samples have a central domain wall, as well as other types of domain walls, if the nanostructures are wide enough.