Usage:
poly.Stroke.linecap = "";
Where "" can be "solid|dot|dash|dashdot|longdash|longdashdot|longdashdotdot", and first letter must be capitalized
Example:
var points = new Array(
new VELatLong(53.199451902831555, -88.54980468750001),
new VELatLong(51.289405902716794, -82.35351562500001),
new VELatLong(49.38237278700955, -85.517578125),
new VELatLong(51.72702815704775, -90.48339843750001),
new VELatLong(53.146770330850835, -88.59375000000001)
);
var poly = new VEPolyline('polyline1',points);
poly.SetColor(new VEColor(0 , 150 , 100 , 1.0));
poly.Stroke.linecap = "Dot";
map.AddPolyline(poly);
PS: other line types
Solid, ShortDash, ShortDot, ShortDashDot, ShortDashDotDot, Dot, Dash, LongDash, DashDot, LongDashDot, LongDashDotDot