Here's what i do
WP page,
WP option,
input LL (as called, add leading zero for longitude). on scratch pad, OSB 17 followed by osb16,
when detail is entered correctly, click the OSB9 to add as waypoint, (note the wp number first)
steerpoint switch to mission,
Hud soi, dms up/down to select the waypoint.
TAD, soi, zoom out, hook the marker,
DMS up long to make it spi.
(hope i included everyting)